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Another Cropped Sensor Question
I am not quite sure how to word this question accurately, but here goes:.

I am using a Canon S3 superzoom with an actual zoom ratio of 6-36mm (36-432 apparent). Since it uses such a small sensor, the field of view at 36mm is what the field of view would be with a 432mm lens on a 35mm camera..

Do the same "cropped-sensor" physics come into play with compact digital cameras as do DSLR's when compared with 35mm cameras?.

In other words, the 432mm is just apparent - it is still only 36mm focal length and the apparent zoom is only because the camera is using such a small sensor. One would be far better off with a DSLR with "real world" focal lengths - even if only 150mm instead of the paltry 36 max of the superzooms?.

Does that make sense?.

Thanks,Ralph..

Comments (96)

Of course it makes sense..

Canon Powershot S5is - CHDK..

Comment #1

Richard Rosario wrote:.

Of course it makes sense..

Thanks..

I guess another part to my question would be the question of image size or magnification. Some people choke when I have asked about magnification in the past and start bringing up printed pixels sizes, quantum physics, and other things..

My simple question is if the image will have a greater "real" magnification - or zoom with a 150mm lens on an APS sensor than with the 36mm lens on a 6mm sensor - even though it is the 432mm equivalent on that sensor?.

Ralph..

Comment #2

Kd6vm wrote:.

I am using a Canon S3 superzoom with an actual zoom ratio of 6-36mm(36-432 apparent)..

Actually it's 6-72mm....

Since it uses such a small sensor, the field ofview at 36mm is what the field of view would be with a 432mm lens ona 35mm camera..

The diagonal field of view at 72mm is the same as the diagonal field of view would be on a 42 lens on a 35mm camera. Diagonal is used because the S3 IS sensor has a 4:3 aspect ratio, most 35mm cameras are 3:2..

Do the same "cropped-sensor" physics come into play with compactdigital cameras as do DSLR's when compared with 35mm cameras?.

Yes..

In other words, the 432mm is just apparent.

No, it's just a comparison..

One would be far better off with a DSLR with "real world" focal lengths.

There is nothing magical about focal lengths on 35mm systems. For example on 645 you'd need around 600mm to get the same field of view as 432mm on 35mm. So is 600mm the "real world" focal length? 432mm? 72mm? The answer is you use the focal length needed to get the angle of view you'd like on whatever size sensor or film you've got..

Even if only 150mm instead of the paltry 36 max of the superzooms?.

If you stuck 150mm on APS-C you'd have a wider field of view than 72mm on 1/2.5"..

Does that make sense?.

Nope, not at all..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #3

Kd6vm wrote:.

My simple question is if the image will have a greater "real"magnification - or zoom with a 150mm lens on an APS sensor than withthe 36mm lens on a 6mm sensor - even though it is the 432mmequivalent on that sensor?.

72mm on 1/2.5" will have more magnification than 150mm on APS-C at the same output size. That last part is important. Most people don't look at what is collected on the sensor at the size of the sensor, they blow it up to a size that's more comfortable to view. To get a 1/2.5" image up to a given output size, you've got to magnify it more than APS-C at the same output size. System magnification is the same..

If you have ever used an enlarger this would be obvious. You enlarge more with smaller film formats to get a certain size output (i.e. 8x10 or whatever). And if you want to crop and print just a portion of the neg you enlarge even more. I'm guessing that most people who think 35mm system focal lengths are magical have not done this..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #4

Nickleback wrote:.

Actually it's 6-72mm....

You are absolutely right. I haven't had my cuppa yet this morning, I guess..

Let's assume a beginner in photography read this explanation of cropped sensors:.

Http://www.dpreview.com/learn/?/key=focal%20length%20multiplier.

He (she) would come away thinking, "Gee, the camera with the 300mm lens sees a bigger bird than the camera with the 200mm lens, even though the field of view is the same in both.".

I guess I am wondering if a 360mm lens will "see" a 5X bigger bird than a 72mm lens, regardless of the cropping of any sized sensor..

Ralph..

Comment #5

Kd6vm wrote:.

Let's assume a beginner in photography read this explanation ofcropped sensors:.

Http://www.dpreview.com/learn/?/key=focal%20length%20multiplier.

He (she) would come away thinking, "Gee, the camera with the 300mmlens sees a bigger bird than the camera with the 200mm lens, eventhough the field of view is the same in both.".

You are correct, kind of. On the second set of images, the magnification at the sensor is greater with the 35mm image. You should expect that, as 300mm has more magnification than 200mm. However, when you blow the images up to the same output size, the bird is the same size because the APS-C image will be blown up more (i.e. more magnification). So while the lens magnification is different, the system magnification is the same..

Compare the ratio of sky to bird in both images it is the same. You will get this same ratio on output..

BTW, in the first set of images, even though the bird is the same size on the sensor, the bird in the APS-C image will appear larger at the same size output. Again, compare the ratio of sky to bird. The 35mm image has more sky-to-bird, so in the output it will also have more sky-to-bird, therefore the bird will be smaller..

I guess I am wondering if a 360mm lens will "see" a 5X bigger birdthan a 72mm lens, regardless of the cropping of any sized sensor..

Yes, at the sensor. No, on output of the same size..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #6

Nickleback wrote:.

72mm on 1/2.5" will have more magnification than 150mm on APS-C atthe same output size. That last part is important. Most peopledon't look at what is collected on the sensor at the size of thesensor, they blow it up to a size that's more comfortable to view.To get a 1/2.5" image up to a given output size, you've got tomagnify it more than APS-C at the same output size. Systemmagnification is the same..

If you have ever used an enlarger this would be obvious. You enlargemore with smaller film formats to get a certain size output (i.e.8x10 or whatever). And if you want to crop and print just a portionof the neg you enlarge even more. I'm guessing that most people whothink 35mm system focal lengths are magical have not done this..

You may have already answered my question. But it takes time for this thick skull to read, reread, and finally comprehend..

Ralph.

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #7

Kd6vm wrote:.

Let's assume a beginner in photography read this explanation ofcropped sensors:.

BTW, I agree the wording is confusing and the images shown are incomplete. There should be more mention of output enlargement (it's only in footnote 2), and the page should show final output along with images on sensor to make things obvious..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #8

Kd6vm wrote:.

You may have already answered my question. But it takes time forthis thick skull to read, reread, and finally comprehend..

It's tricky because you don't ever see the image on the sensor (except on the page you linked to, and similar pages). You just see the final output. So this talk of magnification at the sensor is a little hard to follow..

If you look at film negatives of different sizes it's more obvious..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #9

There is no cropping. Even if there was, there is no magnification involved with cropped sensors..

A digicam has a tiny sensor matched to a tiny lens. 35 mm (full frame) has a large sensor matched to a large lens. Cropped sensors show only a portion of the image coming through the lens, a crop of it. It's like showing an image on a screen with a projector so that the entire screen is covered. Pretend thats 35 mm. Now put a smaller screen in the same place.

The light hitting the screen, just as light hitting a sensor, is exactly the same. There is no magnification, nothing has changed. Only the screen size has changed. It shows a smaller portion of the projection and therefore shows a different field of view...

Comment #10

Nickleback wrote:.

BTW, I agree the wording is confusing and the images shown areincomplete. There should be more mention of output enlargement (it'sonly in footnote 2), and the page should show final output along withimages on sensor to make things obvious..

Again, to the uninformed (me), it sure looks like the size of the bird on the 35mm frame is actually larger than the bird on the APS sensor..

I appreciate your helpful answers, but I would like the physics involved to become clear to me. AND, I understand that it may never become clear..

Zoom cameras are advertised as being able to "get you close to the action", etc. Do the longer focal length lenses actually "get you closer"? Or is everything just relative to the size of the sensor..

They make long focal length telescopes for detailed study of planetary features, because the image at the eypiece or sensor is actually larger with longer focal lengths than with short ones. Granted, you can change the magnification just by changing the eyepiece, but that long focal length is designed for more detail. I am wondering if the same physics apply..

Thanks for your help so far,Ralph..

Comment #11

My impression here is that some parts of the questions are bordering on philosophy rather than photography..

For example "the camera with the 300mm lens sees a bigger bird than the camera with the 200mm lens". Normally, when we talk about "seeing" something such as a bird, the bird remains unchanged regardless of what method we use to observe it..

The only answers in terms of photography must be expressed in terms of properties of the image that can be described and measured..

Obviously we can measure the fact that the image produced on the sensor by different focal length lenses will be of different sizes. But we never actually look at the optical image produced by the lens on the sensor itself. We only ever look at a display, on paper or screen, of the image data gathered by the sensor, so in that sense the sensor size is irrelevant..

So let's move on to other things which we can observe and measure. These might include:" image detail (e.g. feathers on the bird)" image noise" depth of field (branches behind the bird in/out of focus).

These are the sorts of things that are relevant when considering the advantages or disadvantages of different-sized camera systems..

And these things relate specifically to the properties of te sensor and properties of the lens. Such as noise from the sensor, chromatic aberration from the lens and so on.Regards,Peter..

Comment #12

Kd6vm wrote:.

Again, to the uninformed (me), it sure looks like the size of thebird on the 35mm frame is actually larger than the bird on the APSsensor..

In the 300mm on 35mm vs 200mm on APS-C images (i.e. the second set), the bird is larger on 35mm. Now blow up both to 8x10. The APS-C needs to be blown up more to reach 8x10. At 8x10 (or whatever, as long as you use the same output size for both), the bird in each image is the same size..

Zoom cameras are advertised as being able to "get you close to theaction", etc. Do the longer focal length lenses actually "get youcloser"?.

On the same size sensor, yes. If the sensors are a different size, then it depends on the focal lengths involved..

Or is everything just relative to the size of the sensor..

Precisely. Note that in the second set of images, the bird is the same size relative to the frame size (or as I put it, relative to the sky)..

They make long focal length telescopes for detailed study ofplanetary features. Granted, you can change the magnification justby changing the eyepiece.

Yes, this is analogous to output size..

But that long focal length is designed formore detail. I am wondering if the same physics apply..

I don't know telescopes very well, but I thought aperture size (i.e. physical size, not ratio as is used on cameras) is more important than focal length. A larger aperture collects more light. Magnification is a combination of telescope focal length and eyepiece focal length..

Thanks for your help so far,.

You're welcome..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #13

Wmsson wrote:.

There is no cropping. Even if there was, there is no magnificationinvolved with cropped sensors..

My point exactly. The image just occupies a greater percentage of the field of view, and the image only seems bigger..

A digicam has a tiny sensor matched to a tiny lens. 35 mm (fullframe) has a large sensor matched to a large lens. Cropped sensorsshow only a portion of the image coming through the lens, a crop ofit. It's like showing an image on a screen with a projector so thatthe entire screen is covered. Pretend thats 35 mm. Now put a smallerscreen in the same place.

The lighthitting the screen, just as light hitting a sensor, is exactly thesame. There is no magnification, nothing has changed. Only the screensize has changed. It shows a smaller portion of the projection andtherefore shows a different field of view..

Understood. Good illustration...

Comment #14

Sherwoodpete wrote:.

My impression here is that some parts of the questions are borderingon philosophy rather than photography..

You're right. That is why my question was very difficult to frame in words to convey my thoughts..

For example "the camera with the 300mm lens sees a bigger bird thanthe camera with the 200mm lens". Normally, when we talk about"seeing" something such as a bird, the bird remains unchangedregardless of what method we use to observe it.The only answers in terms of photography must be expressed in termsof properties of the image that can be described and measured.Obviously we can measure the fact that the image produced on thesensor by different focal length lenses will be of different sizes..

I can conclude therefore, that the longer focal length lenses used with APC cameras (as opposed to compact digicams) will produce a larger image on the sensor, and hence require less magnification for a usable image - either on the screen or on paper..

But we never actually look at the optical image produced by the lenson the sensor itself. We only ever look at a display, on paper orscreen, of the image data gathered by the sensor, so in that sensethe sensor size is irrelevant.So let's move on to other things which we can observe and measure.These might include:" image detail (e.g. feathers on the bird)" image noise" depth of field (branches behind the bird in/out of focus).

These are the sorts of things that are relevant when considering theadvantages or disadvantages of different-sized camera systems.And these things relate specifically to the properties of te sensorand properties of the lens. Such as noise from the sensor, chromaticaberration from the lens and so on.Regards,Peter.

Thanks for your thoughful reply..

Ralph..

Comment #15

Kd6vm wrote:.

Some people choke when I have asked aboutmagnification in the past and start bringing up printed pixels sizes,quantum physics, and other things..

Guess you are referring to me and others discussing there. Really sorry over there. Wasn't mean to confuse you..

My simple question is if the image will have a greater "real"magnification - or zoom with a 150mm lens on an APS sensor than withthe 36mm lens on a 6mm sensor - even though it is the 432mmequivalent on that sensor?.

My apology by giving a focused answer this time:.

As long as "real" focal length is the same, the "real" magnification is the same..

"35mm equivalent" focal length is only for us compare the FOV (same "35mm equivalent" focal length get the same FOV).

Example:.

When you reduce your sensor size by crop factor of 6 compare to full frame, you need to reduce your "real" magnification by a factor of 6 to get the same FOV. Hence, you reduce your "real" focal length by 6, hence 36mm-432mm divide by 6 gives you 6mm-72mm (the "real" focal length of your compact camera)..

Hope it wasn't too confusing this time...

Comment #16

Kd6vm wrote:.

I can conclude therefore, that the longer focal length lenses usedwith APC cameras (as opposed to compact digicams) will produce alarger image on the sensor, and hence require less "magnification" fora usable image - either on the screen or on paper..

Exactly. But as the other guy suggested last time, to avoid confusion caused by wordings, we should use "enlargement" to replace "magnification" in this statement. It is like we enlarge the image from sensor on the screen or paper. "Magnification" is always something do to with optics..

Just some food for thought as most of us were quite confused in the discussion last time...

Comment #17

Skylark_khur wrote:.

Kd6vm wrote:.

Some people choke when I have asked aboutmagnification in the past and start bringing up printed pixels sizes,quantum physics, and other things..

Guess you are referring to me and others discussing there. Reallysorry over there. Wasn't mean to confuse you..

Hello again. No, I didn't mean that the way it sounded, either. Your answers were very helpful, it is just I am trying to simplify the question and answer so I can get my mind around the advantages of a larger lens..

It seems that some of the comments indicate that there is no really no difference whether you use a 4X5" sensor with an appropriate sized lens or a 2mm sensor with a matching sized lens- that as long as the focal length to sensor size ratio remains the same, everything else will be the same as well..

We know that there are better quality lenses avaiable for the larger frame cameras than are manufactured for the one-piece super zooms. For arguments sake, let's say some manufacturer built a high-quality lens for the compact camera that had a max focal lengtt of 72mm. Am I to believe that there is no inherent advantage of using a lens with a much larger focal length - that it is only an advantage because I can use it on a camera with a larger sensor that exhibits less noise?.

I am contending that the larger focal length is an advantage all in itself by producing a larger image at the sensor that needs less manipulation to be usable. Am I wrong?.

My simple question is if the image will have a greater "real"magnification - or zoom with a 150mm lens on an APS sensor than withthe 36mm lens on a 6mm sensor - even though it is the 432mmequivalent on that sensor?.

My apology by giving a focused answer this time:As long as "real" focal length is the same, the "real" magnificationis the same..

By "real focal lengths" I was trying to describe focal lengths that are an appreciable percentage of the total sensor to scene distance. Not the very reduced focal lengths in the compacts..

Example:When you reduce your sensor size by crop factor of 6 compare to fullframe, you need to reduce your "real" magnification by a factor of 6to get the same FOV. Hence, you reduce your "real" focal length by6, hence 36mm-432mm divide by 6 gives you 6mm-72mm (the "real" focallength of your compact camera)..

Hope it wasn't too confusing this time..

Not at all! Thanks again for chiming in with a helpful reply..

Ralph..

Comment #18

Skylark_khur wrote:.

Exactly. But as the other guy suggested last time, to avoidconfusion caused by wordings, we should use "enlargement" to replace"magnification" in this statement. It is like we enlarge the imagefrom sensor on the screen or paper. "Magnification" is alwayssomething do to with optics..

I agree that enlargement is the appropriate term. I remember seeing my father make contact prints from the large (6 x 9 cm) negatives from his film camera. The size of the people on the print were identical to the size of the image produced by the camera lens..

Later he got a 35mm camera, with much smaller negatives. These needed to be enlarged in order to make a print big enough to view comfortably..

The terminology seems to make sense when we consider making prints (or just an on-screen display) from digital camera images..

Regards,Peter..

Comment #19

Kd6vm wrote:.

It seems that some of the comments indicate that there is no reallyno difference whether you use a 4X5" sensor with an appropriate sizedlens or a 2mm sensor with a matching sized lens.

Correct, in terms of field of view..

Circle of confusion (CoC) (in simple terms, the size of the largest dot on the sensor/film that appears sharp when enlarged) will need to be smaller on the smaller sensor, because you are enlarging more for final output. Depth of field at the same aperture ratio will be larger on the smaller sensor too, due to smaller CoC and smaller aperture diameter..

As long as thefocal length to sensor size ratio remains the same, everything elsewill be the same as well..

If you want everything the same, including depth of field, you need to divide the aperture ratio by the same ratio that you divided the focal length. For instance, 200mm f/4 on 35mm yields the same field of view and same depth of field as 100mm f/2 on a sensor half the size (i.e. 4/3"). Of course the shutter speed on the 35mm image will be slower, unless you up the ISO by the ratio squared..

So to have everything equal, 200mm f/4 ISO 400 on 35mm yields the same shot as 100mm f/2 ISO 100 on 4/3" (although in this case the aspect ratio is different, so the 4:3 image will see more vertically, and 3:2 more horizontally)..

We know that there are better quality lenses avaiable for the largerframe cameras than are manufactured for the one-piece super zooms..

Smaller lenses are easier to make at high quality. Large format negatives usually aren't nearly as sharp as 35mm negatives. They don't have to be, as for the same output size you don't need to enlarge 4x5 nearly as much as 35mm..

As for 1/2.5" cameras vs APS-C, you'll often find that resolution is about the same given the same number of pixels. To do this, the 1/2.5" lens has to resolve much finer detail than the APS-C lens..

For arguments sake, let's say some manufacturer built a high-qualitylens for the compact camera that had a max focal lengtt of 72mm. AmI to believe that there is no inherent advantage of using a lens witha much larger focal length - that it is only an advantage because Ican use it on a camera with a larger sensor that exhibits less noise?.

A much larger focal length at the same aperture ratio brings in more light. That's why larger sensors exhibit less noise. More light means more signal..

Shot noise is proportional to the square root of photons collected. If you collect 100 photons, signal to noise is 10:1. If you collect 10,000 photons, signal to noise is 100:1..

Shot noise isn't the only noise, but it's a big component of noise, especially with smaller sensors..

I am contending that the larger focal length is an advantage all initself..

You are mistaking cause and effect. A larger sensor is an advantage. To get the same field of view on a larger sensor as compared to a smaller sensor, you need a longer focal length..

By "real focal lengths" I was trying to describe focal lengths thatare an appreciable percentage of the total sensor to scene distance..

That's irrelevant. What's relevant is focal length to sensor size..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #20

Kd6vm wrote:.

It seems that some of the comments indicate that there is no reallyno difference whether you use a 4X5" sensor with an appropriate sizedlens or a 2mm sensor with a matching sized lens- that as long as thefocal length to sensor size ratio remains the same, everything elsewill be the same as well..

Ya, as long as the ratio remains the same, the field of view is the same, and you get the similar photo. The only different here is the larger sensor gives cleaner and sharper image..

Edited: I forget to mentioned depth of field here. They will be different as pointed out above..

For arguments sake, let's say some manufacturer built a high-qualitylens for the compact camera that had a max focal lengtt of 72mm. AmI to believe that there is no inherent advantage of using a lens witha much larger focal length - that it is only an advantage because Ican use it on a camera with a larger sensor that exhibits less noise?.

The advantage is really came from the larger sensor. The lens of compact camera actually need to be higher in quality than full-frame camera lense because it need to produce the small sharp image on small sensor. Where as, you can use a lousier lens to produce the larger but not-so-sharp image on big sensor. And yet, when enlarge to view on screen at same size, you get the same sharpness...

Comment #21

Skylark_khur wrote:.

"Magnification" is always something do to with optics..

Enlargers have optics..

Now I know what you are going to say. There are no optics in digital enlargement. That's true, and it is an advantage. No optic is perfect. Digital enlargement, while also not perfect, typically has the same effect across the entire image..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #22

Sherwoodpete wrote:.

Skylark_khur wrote:.

Exactly. But as the other guy suggested last time, to avoidconfusion caused by wordings, we should use "enlargement" to replace"magnification" in this statement. It is like we enlarge the imagefrom sensor on the screen or paper. "Magnification" is alwayssomething do to with optics..

I agree that enlargement is the appropriate term. I remember seeingmy father make contact prints from the large (6 x 9 cm) negativesfrom his film camera. The size of the people on the print wereidentical to the size of the image produced by the camera lens.Later he got a 35mm camera, with much smaller negatives. These neededto be enlarged in order to make a print big enough to viewcomfortably.The terminology seems to make sense when we consider making prints(or just an on-screen display) from digital camera images..

Regards,Peter.

I think this is where I got confused in the last thread..

A long focal length lens will produce a larger image at the film, eyepiece, or sensor. I guess I didn't see any difference whether this lens property was referred to as enlargement or magnification. Indeed, the term enlargement does belong to the realm of darkrooms and scanners, etc. I guess my use of the word "magnification" was my attempt at understanding the process. Maybe because I remember using a "magnifying" glass as a kid?.

Ralph..

Comment #23

I foresee we are going to go too technical in "Beginners Questions" again with all the jargons coming in..

I try my best to describe it simple here for what I said about using lousier optics for full-frame here again..

If you would like to enlarge both images (A from smaller sensor, B from larger sensor) to the same printing size, you need the original image A to be sharper than B to get the same final printing sharpness. Hence, you need a higher quality optics to produce the sharper original image A..

Thus, that is why the author of the link that you provided last time said that you can use cheaper and lousier lens on full frame...

Comment #24

Skylark_khur wrote:.

I foresee we are going to go too technical in "Beginners Questions"again with all the jargons coming in..

You're right. I will be getting my Sony A200 within a couple of days. I guess the best form of learning is "hands on." I will do plenty of experimenting in the coming weeks. Thanks for your help so far..

I try my best to describe it simple here for what I said about usinglousier optics for full-frame here again..

If you would like to enlarge both images (A from smaller sensor, Bfrom larger sensor) to the same printing size, you need the originalimage A to be sharper than B to get the same final printingsharpness. Hence, you need a higher quality optics to produce thesharper original image A..

Thus, that is why the author of the link that you provided last timesaid that you can use cheaper and lousier lens on full frame..

Yes, he did make that point. But some of the pictures he used as examples of APS-C output were clearlly inferior to most I have seen, and left me with the impression that he was weighting the evidence in his favor. That was all..

Thanks again,Ralph..

Comment #25

Kd6vm wrote:.

You're right. I will be getting my Sony A200 within a couple ofdays. I guess the best form of learning is "hands on.".

It's easy. You get what you see. Forget the focal length crop factor, just look through the viewfinder. You did fine with this method using a digicam, right..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #26

Nickleback wrote:.

It's easy. You get what you see. Forget the focal length cropfactor, just look through the viewfinder..

This might just be the best advice ever!.

You did fine with this method using a digicam, right..

Mostly. But have always been technically interested in what the bigger optics coud do - and why they do them..

Thanks a lot for your input. Always welcome..

Ralph..

Comment #27

Kd6vm wrote:.

I can conclude therefore, that the longer focal length lenses usedwith APC cameras (as opposed to compact digicams) will produce alarger image on the sensor, and hence require less magnification fora usable image - either on the screen or on paper..

Yes it will project a larger image onto the sensor. It has to. It's a bigger sensor. But if both cameras are 8 mp, they will produce the same size image on your computer screen..

If you're thinking about cropping images to get a closer field of view, that can work. But if both cameras are 8 mp and you take the same photo (the same field of view) that doesn't mean you can use only 200mm (35 mm equivalent) on the larger sensor and 100mm equivalent on the smaller sensor camera..

You must be thinking that the camera's original ouput is the same size as the sensor just like a film negative is a film cameras original ouput. It doesn't work that way with digital. The size of the camera's ouput depends on the megapixel count. Both 8 mp cameras have 8 million photosites collecting information. (That's not accuratte but makes it easier to understand)The smaller sensor simply has smaller photosites. The original ouput from each camera is what you see on your computer screen and if they're both 8 mp they'll be the same size..

You're thinking about it all more than is necessary. All you need to know when going to a camera with a different sized sensor is the focal lengths of the lenses you need to get the same photos you got from your other camera. 35 mm is the standard. We use multipliers for digicams and crop factors for cropped sensor cameras. Find out that number, do the math and these are the focal lengths you need with the new camera to get the same fields of view as your old one..

If your new camera has a much higher mp count than the old one, yes you can crop your images to get a different apparent field of view, get the same photo with a lower focal length lens than the crop factor would suggest. But you can only do this to a point. It's not a practical way to do it. It's waht we do because we don't have lenses with enough reach. With only 432 mm equivalent on your megazoom are you not already needing to crop some of your photos? If you are, then maybe even more zoom is what you want when you get a Dslr, not less...

Comment #28

Wmsson wrote:.

Kd6vm wrote:.

I can conclude therefore, that the longer focal length lenses usedwith APC cameras (as opposed to compact digicams) will produce alarger image on the sensor, and hence require less magnification fora usable image - either on the screen or on paper..

Yes it will project a larger image onto the sensor. It has to. It's abigger sensor. But if both cameras are 8 mp, they will produce thesame size image on your computer screen..

Thinking in MP is misleading. Simply said, to put the same image at the same size on the screen, the smaller sensor image is enlarged more. Whether the image needs to be uprezzed or downrezzed to fit on the screen, and to what degree, doesn't change this, it simply is a difference in potential resolution..

You must be thinking that the camera's original ouput is the samesize as the sensor just like a film negative is a film camerasoriginal ouput. It doesn't work that way with digital..

It does..

The size ofthe camera's ouput depends on the megapixel count..

The potential resolution depends on the megapixel count. The enlargement used depends on the size of the sensor..

For example, if you shoot with a 3mp DSLR (like the old Canon D30, not to be confused with the 30D) and a 12mp DSLR (like the Canon 450D), the image enlargement is the same. However the 12mp sensor has the potential for higher resolution (and unless the lens is a pinhole, will have higher resolution)..

This is really no different in film. You could buy high resolution film (fine grained B&W), low resolution film (consumer ISO 800), and anything in between. 3mp is low resolution, 12mp doesn't approach high resolution film....

If your new camera has a much higher mp count than the old one, yesyou can crop your images to get a different apparent field of view.

You can even do this with your older, lower resolution camera, Regardless of which one you crop, you will lose resolution. However cropping a higher resolution image will more likely give pleasing results. Again, this is no different that film..

It's not apractical way to do it. It's waht we do because we don't have lenseswith enough reach..

Cropping is usually done because you can't always figure out what part of the scene you want for final output, or what aspect ratio you want, or the output aspect ratio doesn't match your camera's. So you shoot a bit wide and crop later..

For example, if you are shooting a group shot that you think you want to print as a landscape 8x10, you'd better not put people on the edge of the frame because they'll be cut off when you crop for 8x10..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #29

Kd6vm wrote:.

I am not quite sure how to word this question accurately, but here goes:.

I am using a Canon S3 superzoom with an actual zoom ratio of 6-36mm(36-432 apparent). Since it uses such a small sensor, the field ofview at 36mm is what the field of view would be with a 432mm lens ona 35mm camera..

Do the same "cropped-sensor" physics come into play with compactdigital cameras as do DSLR's when compared with 35mm cameras?.

In other words, the 432mm is just apparent - it is still only 36mmfocal length and the apparent zoom is only because the camera isusing such a small sensor. One would be far better off with a DSLRwith "real world" focal lengths - even if only 150mm instead of thepaltry 36 max of the superzooms?.

Does that make sense?.

Thanks,Ralph.

Yes, the field of view is equivalent in the scenario you describe above; it's good that you understand the difference between focal length (a lense property) and field of view (what you call "apparent zoom")..

However, it takes a lot less effort and a lot less money to make a 36mm (432mm equivalent) f/3.5 lense than it does to make a 432mm (432mm equivalent) f/3.5 lense. For example, I'm guessing your S3 camera costs no more than $500. A 432mm f/3.5 for a 35mmFF DSLR is going to cost around $5,500. So while you are correct in that having the "real focal length" equivalent field of view is essentially "better," you are also paying an arm and a leg for it..

With respect to this in another of your posts:.

I guess another part to my question would be the question of image size or >magnification. Some people choke when I have asked about magnification in the >past and start bringing up printed pixels sizes, quantum physics, and other things..

Magnification is solely determined by the lense and the sensor. Don't think of magnification how you would with a magnifying glass, it's different..

Understanding 1:1 magnification is the easiest so let's start there. If your camera/lense has 1:1 magnificationhas, and the camera has a sensor that is 1"x1" then it can focus on an object that is also 1"x1" and that object will exactly fill the entire sensor's pixels. In other words, a 1:1 correlation..

Take that same 1"x1" sensor and 1"x1" object, but now let's say you can only focus so that the object fills exactly half of your sensor's pixels (right in the middle, for example). Then your camera/lense combo has a 1:2 magnification..

It's essentially useless to quote magnification for telephoto lenses and extrapolate that magnification to how "close" you can bring a subject. For example, a 300mm lense can have 0.15X magnification while a 200mm lense can have 0.21X magnification. You would "think" the 0.21X would bring the subject closer, but in reality the 300mm lense will get you much, much closer to your subject. (data taken from Olympus's lense lineup).

So for all intents and purposes magnification is only used for macro lenses, whose design allows them to focus closer to the subject, thus enhancing magnification..

As a side note, an extension tube can be added to most lenses to enhance the magnification as well, at the cost of infinite focus. (That's another lesson in-and-of itself).

Tim'Be the change you wish to see in the world.' -Mahatma GandhiE3/E1/7-14/12-60/50-200/EC-14/C8080http://www.flickr.com/photos/timskis6/..

Comment #30

Here is just one example of how confusing the study of different lenses can be. Concerning lenses for full frame vs. cropped sensor, this site's review of the Canon 5d states:.

"....a full frame sensor puts a higher requirement on the quality of the lens.."http://www.dpreview.com/reviews/canoneos5d/page12.asp.

While beloved, immortal, all-wise Ken Rockwell says:.

"I get better results on full-frame with crummy lenses than I do with my very best lenses on DX (Nikon D200).".

Http://www.kenrockwell.com/tech/full-frame-advantage.htm.

Apparently, I am not the only confused one..

Ralph..

Comment #31

Timskis6 wrote:.

Yes, the field of view is equivalent in the scenario you describeabove; it's good that you understand the difference between focallength (a lense property) and field of view (what you call "apparentzoom")..

However, it takes a lot less effort and a lot less money to make a36mm (432mm equivalent) f/3.5 lense than it does to make a 432mm(432mm equivalent) f/3.5 lense. For example, I'm guessing your S3camera costs no more than $500. A 432mm f/3.5 for a 35mmFF DSLR isgoing to cost around $5,500. So while you are correct in that havingthe "real focal length" equivalent field of view is essentially"better," you are also paying an arm and a leg for it..

Understood. But you seem to agree that a "real focal length" lens is inherently better to have. I just feel this way because of my studies in Astronomy. They wouldn't build a telescope the length of Wall St. if they could get buy building one the size of my S3..

Magnification is solely determined by the lense and the sensor.Don't think of magnification how you would with a magnifying glass,it's different..

Again, in a previous thread I compared the camera's lens/sensor relationship to the relationship between an objective lens and eyepiece in a telescope - however, not in a strict fashion. The sensor itself doesn't have it's own focal length to create a "magnification factor"..

Understanding 1:1 magnification is the easiest so let's start there.If your camera/lense has 1:1 magnificationhas, and the camera has asensor that is 1"x1" then it can focus on an object that is also1"x1" and that object will exactly fill the entire sensor's pixels.In other words, a 1:1 correlation..

Take that same 1"x1" sensor and 1"x1" object, but now let's say youcan only focus so that the object fills exactly half of your sensor'spixels (right in the middle, for example). Then your camera/lensecombo has a 1:2 magnification..

It's essentially useless to quote magnification for telephoto lensesand extrapolate that magnification to how "close" you can bring asubject. For example, a 300mm lense can have 0.15X magnificationwhile a 200mm lense can have 0.21X magnification. You would "think"the 0.21X would bring the subject closer, but in reality the 300mmlense will get you much, much closer to your subject. (data takenfrom Olympus's lense lineup).

So for all intents and purposes magnification is only used for macrolenses, whose design allows them to focus closer to the subject, thusenhancing magnification..

As a side note, an extension tube can be added to most lenses toenhance the magnification as well, at the cost of infinite focus.(That's another lesson in-and-of itself).

Thank you. And I guess I would have to backtrack a little and agree that it is maybe needful to introduce a little bit of quantum physics to explain all that is involved. All of these comments have been most helpful..

Ralph..

Comment #32

Timskis6 wrote:.

It's essentially useless to quote magnification for telephoto lensesand extrapolate that magnification to how "close" you can bring asubject. For example, a 300mm lense can have 0.15X magnificationwhile a 200mm lense can have 0.21X magnification..

The spec is max maginification, which is typically at the shortest focus distance. Longer lenses don't usually focus as close, so they have less maximum magnification..

But let's say you are taking a picture of a far away battleship. The battleship is 250m long, but with your 300mm lens it occupies 18mm on your sensor. So the magnification is 18/250,000, or 0.000072. Next you swap out the 300mm lens and stick on a 200mm lens. The battleship now occupies 12mm on your sensor. The magnification is 0.000048..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #33

Nickleback wrote:.

Timskis6 wrote:.

It's essentially useless to quote magnification for telephoto lensesand extrapolate that magnification to how "close" you can bring asubject. For example, a 300mm lense can have 0.15X magnificationwhile a 200mm lense can have 0.21X magnification..

The spec is max maginification, which is typically at the shortestfocus distance. Longer lenses don't usually focus as close, so theyhave less maximum magnification..

But let's say you are taking a picture of a far away battleship. Thebattleship is 250m long, but with your 300mm lens it occupies 18mm onyour sensor. So the magnification is 18/250,000, or 0.000072. Nextyou swap out the 300mm lens and stick on a 200mm lens. Thebattleship now occupies 12mm on your sensor. The magnification is0.000048..

Yep, Tim was right. That's essentially useless. .

But you did it very well....

Charlie DavisNikon 5700, Sony R1, Nikon D300HomePage: http://www.1derful.infoBridge Blog: http://www.here-ugo.com/BridgeBlog/'Experience: Discovering that a claw hammer will bend nails.Epiphany: Discovering that a claw hammer is two tools...'..

Comment #34

Kd6vm wrote:.

Here is just one example of how confusing the study of differentlenses can be. Concerning lenses for full frame vs. cropped sensor,this site's review of the Canon 5d states:.

"....a full frame sensor puts a higher requirement on the quality ofthe lens.."http://www.dpreview.com/reviews/canoneos5d/page12.asp.

While beloved, immortal, all-wise Ken Rockwell says:.

"I get better results on full-frame with crummy lenses than I do withmy very best lenses on DX (Nikon D200).".

Http://www.kenrockwell.com/tech/full-frame-advantage.htm.

Apparently, I am not the only confused one..

Ralph.

This is again, I believe, confusion caused by terminology. The "quality" that was mean by the reviewer and Ken Rockwell should be different..

The "crummy lenses" means by Ken Rockwell mostly means "crummy" in term of sharpness and resolving resolution. Although he seems exaggerating his claim by providing a very blur image from APS-C, what he said is generally true as some of us explained above..

The "quality" means by the reviewer here possibly means quality as a whole when comparing equivalent FOV (equivalent focal length as we described above) lens..

I give an extreme example here. Let compare compact camera (with the 6 times crop factor sensor) and full frame:.

To achieve the equivalent 36mm-432mm FOV in the compact camera, what we need is just a 6mm-72mm focal length zoom lens. And also, the opening of the lens no need to be very big as it only need to project small image on small sensor. It is easier to create this small lens that maintain it's quality over it's zoom range..

However, if you would really want to achieve 36mm-432mm FOV in full frame, what you need is exactly the 36mm-432mm focal length zoom lens. And also, the opening of the lens need to be a lot larger to project large image on full-frame sensor. This large opening make it very difficult to control the chromatic aberration across the whole lens. This kind of lens doesn't exist so far. It is technical too challenging to create this kind of lens with it's quality maintain over the whole zoom range. If this ever exist, it will be a very bulky lens, and a very high-end lens which the reviewer will call it a very high "quality" lens..

If you ever to go to ask a large format camera user (the film for this is larger than full-frame), they will care less about the sharpness of their lens because they don't need to as mentioned in some previous posts..

Remember, the term "quality" is rather subjective and you should ask yourself what is meant by "quality" here. Is it sharpness, resolving resolution, less chromatic aberration, highly technical to built or other meanings?..

Comment #35

Kd6vm wrote:.

Understood. But you seem to agree that a "real focal length" lens isinherently better to have. I just feel this way because of mystudies in Astronomy. They wouldn't build a telescope the length ofWall St. if they could get buy building one the size of my S3..

If they could build a "super x 100" sharp small optics, they wouldn't want to build the big telescope. They could record the small image from the "super x 100" sharp small optics at "super x 100" high resolution small sensor and enlarge it at computer screen..

The problem is it is technically impossible to build the "super x 100" sharp optics and "super x 100" high resolution sensor. Hence, they build the super big telescope using a lousier optics and low resolution big sensor..

P/s To avoid confusion, high resolution that I mean here is high pixels per inch, not high megapixels. The word "resolution" is always misused. The 8 megapixels 1/2.5" actually is actually of higher resolution than the 8 megapixels full-frame. However, most ppl have started to accept resolution=megapixel. Of course, if sensor A and sensor B are same size, and sensor A is higher in resolution means sensor A has more megapixels (since each pixel is smaller due to high ppi)...

Comment #36

Skylark_khur wrote:.

This is again, I believe, confusion caused by terminology. The"quality" that was mean by the reviewer and Ken Rockwell should bedifferent..

Very likely could have been two different lens issues addressed..

The "crummy lenses" means by Ken Rockwell mostly means "crummy" interm of sharpness and resolving resolution. Although he seemsexaggerating his claim by providing a very blur image from APS-C,what he said is generally true as some of us explained above..

That was my impression, too..

Remember, the term "quality" is rather subjective and you should askyourself what is meant by "quality" here. Is it sharpness, resolvingresolution, less chromatic aberration, highly technical to built orother meanings?.

I don't believe there is as big a difference between full frame quality and APS-C quality, as there is between APS-C and compact digicams. Even that distinction in quality is sometimes barely discernable..

Ralph..

Comment #37

Kd6vm wrote:.

I don't believe there is as big a difference between full framequality and APS-C quality, as there is between APS-C and compactdigicams. Even that distinction in quality is sometimes barelydiscernable..

You crop full-frame 1.8x to get APS-C and 6x to get the 1/2.5".Hence you need to crop APS-C (6/1.8=3.33333)x to get 1/2.5"..

And yes, the different between full frame and APS-C is less than the different between APS-C and compact..

But the benefit of full-frame does not come only from optics, but also dynamic range and less noisy image due to larger sensor area per pixel > where we discuss the noise statistics last time. Lol..

Higher dynamic range as we can collect more photons. Less noise because we can average it out.

P/s When you shooting a still subject on tripod, you can take many same burst shots, and then do averaging to get a cleaner image. (e.g. you sum the value of first pixel from 10 shots and divide it by 10 to get a cleaner first pixel)...

Comment #38

Magnification is solely determined by the lense and the sensor.Don't think of magnification how you would with a magnifying glass,it's different..

Understanding 1:1 magnification is the easiest so let's start there.If your camera/lense has 1:1 magnificationhas, and the camera has asensor that is 1"x1" then it can focus on an object that is also1"x1" and that object will exactly fill the entire sensor's pixels.In other words, a 1:1 correlation..

Take that same 1"x1" sensor and 1"x1" object, but now let's say youcan only focus so that the object fills exactly half of your sensor'spixels (right in the middle, for example). Then your camera/lensecombo has a 1:2 magnification..

Tim:.

The above is almost correct, and your example is good. But note that the size of the sensor doesn't have anything to do with the magnification. Magnification is just the ratio of the size of the image projected on the sensor to the size of the subject itself. At a given focal length and subject distance, a lens will produce the same magnification regardless of the camera is mounted on, or the size of it's sensor..

Davehttp://www.pbase.com/dsjtecserv..

Comment #39

Chuxter wrote:.

Nickleback wrote:.

But let's say you are taking a picture of a far away battleship. Thebattleship is 250m long, but with your 300mm lens it occupies 18mm onyour sensor. So the magnification is 18/250,000, or 0.000072. Nextyou swap out the 300mm lens and stick on a 200mm lens. Thebattleship now occupies 12mm on your sensor. The magnification is0.000048..

Yep, Tim was right. That's essentially useless. .

But you did it very well....

That part is useless. However, let's take this full circle..

We want to print a picture of this battleship at 8x10. We want some blue water in front and behind the ship, so let's say we want the ship to occupy 180mm of the 250mm (10 inches) available..

To get that 18mm on-the-sensor battleship up to 180mm you need to magnify it 10 times. So that's 10 * 0.000072, or 0.00072..

To get that 12mm on-the-sensor battleship up to 180mm, it needs to be magnified 15 times. So that's 15 * 0.000048, or 0.00072..

Notice that the magnification at the print is identical? It should be, as you've got the same size battleship on the print..

Works even for a 4mm on the sensor using a 66.7mm lens, but you have to magnify it 45x for output. Again, different magnification at the sensor, same magnification on the print..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #40

Maybe we should get back to the fundamental of optical physics to describe sharpness which I believe your are more familiar..

Ideally, a perfect lens focus an object point to an image point. This is what we called absolute sharpness..

In reality, perfect lens never occurred. A practical lens focus an object point to a blurred circle (we call it Circle of Confusion). The smaller the diameter of this circle, the sharper is your lens..

Hence, the sharpness is always related to the CoC. Let say you accept that 1mm CoC is considered sharp in your final print. (we usually accept 0.0*** as sharp, but we put 1 for easy discussion). And let say you need to enlarge 10x from full-frame to get the print size, you need the CoC of the project image to be 0.1mm. And at the same time, you need to enlarge 60x from 1/2.5" CCD to get the print size, you need the CoC of the project image to be 0.016667mm (hence, much sharper)...

Comment #41

Skylark_khur wrote:.

To achieve the equivalent 36mm-432mm FOV in the compact camera, whatwe need is just a 6mm-72mm focal length zoom lens. And also, theopening of the lens no need to be very big as it only need to projectsmall image on small sensor..

The opening on the front has nothing to do with what is projected in the back. It has everything to do with aperture. Aperture ratio is focal length/aperture diameter. The front element can't be smaller than this, and for non-telephoto lenses is typically larger. 72mm f/3.1 doesn't need nearly as big a front element as 432mm f/3.1. But then that isn't a fair comparison, as the bigger sensor is collecting a lot more light at f/3.1 than the smaller sensor.

If you instead use 432mm f/18.6 on the 35mm camera, the total amount of light collected is the same. Of course there is no 42mm f/18..6, but if there were one made the lens diameter would be about the same as the 72mm lens (but of course it would be longer)..

Here's a lens with 52mm filter that covers 4x5 inches:.

Http://www.bhphotovideo.com/...GREY/Nikon_1314_150mm_f_5_6_Nikkor_W_Lens.html.

It is easier to create this small lensthat maintain it's quality over it's zoom range..

Yes..

However, if you would really want to achieve 36mm-432mm FOV in fullframe, what you need is exactly the 36mm-432mm focal length zoomlens. And also, the opening of the lens need to be a lot larger toproject large image on full-frame sensor..

The opening has to be larger because SLR buyers really don't want f/18 optics. They want f/5.6 or faster. At 432mm f/5.6, the front element has to be at least 77mm in diameter..

This large opening make itvery difficult to control the chromatic aberration across the wholelens..

That's true..

This kind of lens doesn't exist so far..

Tamron 18-250mm on Canon APS-C is pretty darn close. That's 29-400mm "35mm equivalent". And at f/6.3 on the long end that lens on APS-C is still taking in almost 4x as much light as f/3.1 on 1/2.5"..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #42

Skylark_khur wrote:.

P/s To avoid confusion, high resolution that I mean here is highpixels per inch, not high megapixels. The word "resolution" isalways misused. The 8 megapixels 1/2.5" actually is actually ofhigher resolution than the 8 megapixels full-frame..

At the sensor, yes. On final output, which is all anybody cares about, no..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #43

Dsjtecserv wrote:.

.....Magnification is just the ratio of the size of theimage projected on the sensor to the size of the subject itself. At agiven focal length and subject distance, a lens will produce the samemagnification regardless of the camera is mounted on, or the size ofits sensor..

Dave.

Agreed. Yes, a lens does "magnify" an image. The greater the focal length, the greater the magnification. Again, I am inclined to believe that the greater the actual focal length (real - not equivalent), the bigger the image on the sensor - any sensor, and consequently, a bigger image that needs less enlargment to a suitable size for whatever output is intended..

Ralph..

Comment #44

Kd6vm wrote:.

Agreed. Yes, a lens does "magnify" an image. The greater the focallength, the greater the magnification. Again, I am inclined tobelieve that the greater the actual focal length (real - notequivalent), the bigger the image on the sensor - any sensor.

True..

Andconsequently, a bigger image that needs less enlargment to a suitablesize for whatever output is intended..

True, but maybe not in the way you think..

Let's say you shoot a battleship with 432mm lens on 35mm. You then shoot the same battleship on 1/2.5" with the same 432mm lens mounted (using a hacksaw and duct tape, I assume) and you capture only the bridge..

Enlarge both images the same amount. The 35mm print will show the entire battleship. The 1/2.5" print will only show the bridge. But because you used the same enlargement, the 1/2.5" print is 1/6 the size, and the bridge on both prints are the same size..

However if you want more detail on the bridge, chances are pretty good that the 1/2.5" image can be enlarged a lot more, as you've got the full 8mp (or whatever) on the bridge, whereas a 20mp 35mm camera would have 0.6mp on the bridge..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #45

The opening on the front has nothing to do with what is projected inthe back. It has everything to do with aperture. Aperture ratio isfocal length/aperture diameter. The front element can't be smallerthan this, and for non-telephoto lenses is typically larger. 72mmf/3.1 doesn't need nearly as big a front element as 432mm f/3.1. Butthen that isn't a fair comparison, as the bigger sensor is collectinga lot more light at f/3.1 than the smaller sensor.

If you instead use 432mm f/18.6 on the 35mm camera, the totalamount of light collected is the same. Of course there is no 42mmf/18..6, but if there were one made the lens diameter would be aboutthe same as the 72mm lens (but of course it would be longer).The opening has to be larger because SLR buyers really don't wantf/18 optics. They want f/5.6 or faster. At 432mm f/5.6, the frontelement has to be at least 77mm in diameter..

True. My mistake for confusion above. The front element of 432mm f/2.8 need to be 6 times the front element of 72mm f/2.8 and, hence, larger optics is needed..

Tamron 18-250mm on Canon APS-C is pretty darn close. That's 29-400mm"35mm equivalent". And at f/6.3 on the long end that lens on APS-Cis still taking in almost 4x as much light as f/3.1 on 1/2.5"..

I wouldn't consider this close to a real 36mm-432mm. The "equivalent" is indeed close although...

Comment #46

Nickleback wrote:.

At the sensor, yes. On final output, which is all anybody caresabout, no..

Yes. Of course resolution of 8 megapixels on A4 = resolution of 8 megapixels on A4, whether the 8 megapixels is from small or large sensor..

But what I would like the OP know is the resolution on sensor, which he cares about noise and sharpness...

Comment #47

Nickleback wrote:.

However if you want more detail on the bridge, chances are prettygood that the 1/2.5" image can be enlarged a lot more, as you've gotthe full 8mp (or whatever) on the bridge, whereas a 20mp 35mm camerawould have 0.6mp on the bridge..

Recall my illustrated explanation for what Nickleback trying to explain here. If you use the same lens (same "real" focal lens), you get the same physical image size on your sensor plane..

Image control:Zoom outZoom 100%Zoom inExpand AllOpen in new window..

Comment #48

Skylark_khur wrote:.

Tamron 18-250mm on Canon APS-C is pretty darn close. That's 29-400mm"35mm equivalent". And at f/6.3 on the long end that lens on APS-Cis still taking in almost 4x as much light as f/3.1 on 1/2.5"..

I wouldn't consider this close to a real 36mm-432mm. The"equivalent" is indeed close although..

But it's not like it couldn't be done..

There are plenty of 28-300mm lenses, as well as the old Canon 35-350L and newer 28-300L IS. If you don't mind a bit longer but not quite as wide, there is the Sigma "Bigma" 50-500mm..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #49

Nickleback wrote:.

But it's not like it couldn't be done..

There are plenty of 28-300mm lenses, as well as the old Canon 35-350Land newer 28-300L IS. If you don't mind a bit longer but not quiteas wide, there is the Sigma "Bigma" 50-500mm..

My mistake again, you are right. I keep on thinking that I can't find it here that I almost forget most wildlife photography use high-end superzoom. So, that would be what the reviewer called high quality lens...

Comment #50

Skylark_khur wrote:.

My mistake again, you are right. I keep on thinking that I can'tfind it here that I almost forget most wildlife photography usehigh-end superzoom..

Wildlife photographers generally use long fast primes, 400mm and up. Although I'm sure there are some that will use long zooms, such as the Sigma 300-800mm f/5.6 or Nikon 200-400mm f/4. But 2x or 2.6x ratio zooms hardly qualify as superzooms..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #51

Nickleback wrote:.

Wildlife photographers generally use long fast primes, 400mm and up.Although I'm sure there are some that will use long zooms, such asthe Sigma 300-800mm f/5.6 or Nikon 200-400mm f/4. But 2x or 2.6xratio zooms hardly qualify as superzooms..

So, in the end, the "real" superzoom is still far from the "equivalent" superzoom..

The "equivalent" superzoom, 36mm-432mm f/2.8-4.8 on most P&S.The Sigma Bigma superzoom, 50mm-500mm f/4-6.3....

The zoom is close, but the speed is....

I never did wildlife photography, but if they use long fast primes, I would think the fast aperture and quality from those primes will be a lot better than the currently available real superzoom - the Sigma Bigma..

Edit:Or perhaps, they carry a few cameras to avoid the need to swap lens?.

I would think that by swapping prime lens, you will lose your chance to shoot a wild animal that move around rather randomly...

Comment #52

There is even a superzoom compact with "equivalent" 36mm-432mm f/2.8 constant aperture, the Panasonic FZ20....

Ok, I think we should stop discussing lens here by bombarding the OP threads...

Comment #53

Skylark_khur wrote:.

So, in the end, the "real" superzoom is still far from the"equivalent" superzoom..

You have the wrong definition of equivalent..

The "equivalent" superzoom, 36mm-432mm f/2.8-4.8 on most P&S.The Sigma Bigma superzoom, 50mm-500mm f/4-6.3....

The zoom is close, but the speed is....

Faster on the Bigma. Although for exposure purposes it is slower, the total light collected is much higher..

First of all, the typical digicam superzoom is around f/3.5 on the long end, not f/4.8..

Second, if you want the same amount of light collected on the 35mm camera the aperture only needs to be 3.5 * 6, or f/21. Nobody makes a f/21 35mm system lens. But that's OK, the bigma is f/6.3. On 35mm it's pulling in more than 10x as much light. That should mean much less noise..

If you object that the exposure is not the same, you are correct. So crank up the ISO on the 35mm camera. The difference between f/3.5 and f/6.3 is less than two stops. The 35mm camera will have the same shutter speed and still less noise..

I never did wildlife photography, but if they use long fast primes, Iwould think the fast aperture and quality from those primes will be alot better than the currently available real superzoom - the SigmaBigma..

Sure, you get what you pay for..

But both the 50-500mm "bigma" and a 6-72mm lens on a 1/2.5" superzoom are real. There is nothing magic about the focal lengths on 35mm system lenses that somehow make them "real" and lenses for other formats not real..

Or perhaps, they carry a few cameras to avoid the need to swap lens?I would think that by swapping prime lens, you will lose your chanceto shoot a wild animal that move around rather randomly..

You pick the focal length that's best for capturing the animal you are trying to shoot. Usually the problem is the lens isn't long enough..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #54

Skylark_khur wrote:.

There is even a superzoom compact with "equivalent" 36mm-432mm f/2.8constant aperture, the Panasonic FZ20....

Equivalent in light captured to 36-432mm f/16 on 35mm. Like I wrote in the previous message, if you don't like the resulting shutter speed, crank the ISO up on the 35mm camera. Take advantage of the better high ISO performance..

Ok, I think we should stop discussing lens here by bombarding the OPthreads..

I'm simply responding to disinformation..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #55

Nickleback wrote:.

Skylark_khur wrote:.

So, in the end, the "real" superzoom is still far from the"equivalent" superzoom..

You have the wrong definition of equivalent..

It is not that I have the wrong definition of equivalent. It is just that you have the different meaning of "equivalent"..

I believe the OP are interested in knowing the "equivalent" in terms of exposure, not the amount of total light collected..

432mm (35mm equivalent) and 432mm real with the same "equivalent" focal length and with the same f-number gives the same exposure under the same ISO..

432mm (35mm equivalent) is used on small sensor to create the same FOV as the 432mm real on full-frame. The surface of the small sensor is so small compare to the full-frame, of course the amount of light collected need not be as much. And, of course, lower amount of light means noiser. Everyone learnt statistics would know about high signal-to-noise ratio means higher quality..

And I believe that most people would mean exposure rather than amount of light collected when talk about "equivalent". If not, why would we want to use the f-stop, which is focal-length/diameter rather than the diameter of aperture itself. Yes, when you 2x the diameter, you 4x the amount of light...

Comment #56

Nickleback wrote:.

Skylark_khur wrote:.

There is even a superzoom compact with "equivalent" 36mm-432mm f/2.8constant aperture, the Panasonic FZ20....

Equivalent in light captured to 36-432mm f/16 on 35mm. Like I wrotein the previous message, if you don't like the resulting shutterspeed, crank the ISO up on the 35mm camera. Take advantage of thebetter high ISO performance..

Stopping from f/5.6 to f/2.8 (2-stop) is just like cranking the ISO up for 4 times (e.g. 100-400) for getting the same exposure..

By widening your aperture, you get amplify the real signal (the light) without amplifying the noise and by cranking ISO, you simply set higher gain and amplify the real signal together with the noise..

Having ability to up 1-stop of aperture is way better than having ability to crank your ISO higher by 1-stop in term of noise performance...

Comment #57

Skylark_khur wrote:.

I believe the OP are interested in knowing the "equivalent" in termsof exposure, not the amount of total light collected..

Define exposure. To me it's a combination of shutter speed, aperture and ISO. For example, 1/500 f/3.5 ISO 100 is the same exposure as 1/500 f/7 ISO 400..

If you'd like to define exposure in terms of "the images look the same", the only way you can do this if you shoot f/3.5 on 1/2.5" is to shoot f/21 on 35mm, otherwise the DOF will be different..

To keep the shutter speed the same, adjust ISO by the same factor squared..

At this point, both cameras are receiving the same amount of light, so noise should also be equivalent..

At the same DOF, 35mm cameras have no advantage over 1/2.5" cameras. Where 35mm cameras do have an advantage, the DOF will be shorter..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #58

Nickleback wrote:.

The "equivalent" superzoom, 36mm-432mm f/2.8-4.8 on most P&S.The Sigma Bigma superzoom, 50mm-500mm f/4-6.3....

Faster on the Bigma.

No, faster on "equivalent"..

Although for exposure purposes it is slower, the total light collected is muchhigher..

Yes, we talk about speed for exposure purposes, not total light collected. We don't need as much light to cast on small sensor than big sensor to get the same exposure...

Comment #59

Skylark_khur wrote:.

Stopping from f/5.6 to f/2.8 (2-stop) is just like cranking the ISOup for 4 times (e.g. 100-400) for getting the same exposure..

Correct, but you have it reversed. Should read f/2.8 to f/5.6..

You can also do it with shutter speed. Exposure has 3 variables..

By widening your aperture, you get amplify the real signal (thelight) without amplifying the noise and by cranking ISO, you simplyset higher gain and amplify the real signal together with the noise..

Also correct..

Having ability to up 1-stop of aperture is way better than havingability to crank your ISO higher by 1-stop in term of noiseperformance..

Absolutely. Now check the noise performance of 35mm, like the recently reviewed Nikon D3, to whatever 1/2.5" camera you'd like. Cranking the ISO on the D3 two stops will still give you lower noise than any 1/2.5" camera. That's to be expected, because even at 2 stops down the 35mm sensor is collecting more light (i.e. getting more signal) than the 1/2.5" sensor..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #60

Skylark_khur wrote:.

Yes, we talk about speed for exposure purposes.

You are artificially limiting the definition of equivalent. I'm not blaming you, camera marketers have been spouting this for years..

The job of marketing is to show off on stuff that makes them look good, and try to hide stuff that makes them look bad. So they crow about 72mm = 432mm, but fail to mention the other side of the same coin, which is aperture..

I don't like marketing..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #61

Nickleback wrote:.

Define exposure. To me it's a combination of shutter speed, apertureand ISO. For example, 1/500 f/3.5 ISO 100 is the same exposure as1/500 f/7 ISO 400..

Yes..

If you'd like to define exposure in terms of "the images look thesame", the only way you can do this if you shoot f/3.5 on 1/2.5" isto shoot f/21 on 35mm, otherwise the DOF will be different..

No, we don't define it for "images look the same", we define it for same FOV, not DOF.300mm (real), f/4 on full-frameis equivalent to300mm (35-mm equivalent), f/4 on others.Of course, if the APS-C sensor is 1.8x crop, both DOF will be different..

To keep the shutter speed the same, adjust ISO by the same factorsquared..

At this point, both cameras are receiving the same amount of light,so noise should also be equivalent..

At the same DOF, 35mm cameras have no advantage over 1/2.5" cameras.Where 35mm cameras do have an advantage, the DOF will be shorter..

Again, when we means equivalent, it means same FOV and same exposure, not same DOF. 6mm on 1/2.5" is call 300mm (35mm-equivalent) is because it create the same FOV on 1/2.5" as 300mm on 35mm. We don't care about DOF when talking about equivalent. Also, we don't care about receiving same amount of light..

300mm f/4 on 35mm is equivalent to 50mm f/4 on 1/2.5" in our context, which widely use by manufacturer in giving out the specifications..

Of course, the diameter of aperture on 300mm f/4 is 6 times the diameter of aperture on 30mm f/4. Thus, the amount of light entering the camera is 6 square = 36 times. But, we don't care about this when talking about equivalent..

Althought we care about this when talking about noise...

Comment #62

Nickleback wrote:.

Skylark_khur wrote:.

Stopping from f/5.6 to f/2.8 (2-stop) is just like cranking the ISOup for 4 times (e.g. 100-400) for getting the same exposure..

Correct, but you have it reversed. Should read f/2.8 to f/5.6..

No, you are the one who reversed it. f/2.8 is larger than f/5.6.Going from f/5.6 to f/2.8 is +2EV.Going from ISO 100 to ISO 400 is also +2EV..

You can also do it with shutter speed. Exposure has 3 variables..

Of course..

By widening your aperture, you get amplify the real signal (thelight) without amplifying the noise and by cranking ISO, you simplyset higher gain and amplify the real signal together with the noise..

Also correct..

At least you know what I'm talking now..

Having ability to up 1-stop of aperture is way better than havingability to crank your ISO higher by 1-stop in term of noiseperformance..

Absolutely. Now check the noise performance of 35mm, like therecently reviewed Nikon D3, to whatever 1/2.5" camera you'd like.Cranking the ISO on the D3 two stops will still give you lower noisethan any 1/2.5" camera. That's to be expected, because even at 2stops down the 35mm sensor is collecting more light (i.e. gettingmore signal) than the 1/2.5" sensor..

Of course, the reason to use large sensor is to collect more light than small sensor to get the same exposure..

If you really would like to compare, get the same sensor size. Use the same focal length and same shutter speed. Shoot one with f/2.8 ISO 100 and one with f/5.6 ISO 400 and look for the noise..

Don't use the larger sensor advantage...

Comment #63

Nickleback wrote:.

Skylark_khur wrote:.

Yes, we talk about speed for exposure purposes.

You are artificially limiting the definition of equivalent. I'm notblaming you, camera marketers have been spouting this for years..

It is not about marketers, it is about convenient. Most people will care about same exposure and same FOV, thus we talk about equivalent in this context..

Least people care about same DOF and same noise performance, thus we don't talk about equivalent in this context..

Many of these equivalent things is set by the old photographers for their own convenient, not the marketers..

The job of marketing is to show off on stuff that makes them lookgood, and try to hide stuff that makes them look bad. So they crowabout 72mm = 432mm, but fail to mention the other side of the samecoin, which is aperture..

True, they tell you the FOV and exposure is the same. The don't tell you the DOF and noise is not the same..

Also, about super high ISO, they tell you the exposure can get better at low light. They don't tell you it get noisier (but it is too obvious that most ppl see it). Some of them do try to hide it by scaling down the megapixels..

The Panasonic FZ-20 that gives you decent f/2.8 constant can't sell as good as some new camera that gives you f/5.6 at the long end with high ISO stated because the marketing ppl don't know how to sell the big aperture...

Comment #64

Skylark_khur wrote:.

Nickleback wrote:.

Skylark_khur wrote:.

Stopping from f/5.6 to f/2.8 (2-stop) is just like cranking the ISOup for 4 times (e.g. 100-400) for getting the same exposure..

Correct, but you have it reversed. Should read f/2.8 to f/5.6..

No, you are the one who reversed it. f/2.8 is larger than f/5.6..

I know. Sorry, I got messed up by the wording..

You can also do it with shutter speed. Exposure has 3 variables..

Of course..

Then why concentrate on just one: aperture. That's exactly what you are doing by insisting on the same aperture ratio for "equivalence"..

Don't use the larger sensor advantage..

Why not use the larger sensor advantage? You paid for it, use it..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #65

Skylark_khur wrote:.

Nickleback wrote:.

Skylark_khur wrote:.

Yes, we talk about speed for exposure purposes.

You are artificially limiting the definition of equivalent. I'm notblaming you, camera marketers have been spouting this for years..

It is not about marketers, it is about convenient..

If you want convenient, just stick the camera in full auto and it will work out the details regardless of the max aperture of the lens..

Most people willcare about same exposure and same FOV, thus we talk about equivalentin this context..

Same exposure does not require same aperture ratio..

Least people care about same DOF and same noise performance, thus wedon't talk about equivalent in this context..

So you'd prefer to talk about non-equivalent equivalence?.

Many of these equivalent things is set by the old photographers fortheir own convenient, not the marketers..

Old photographers understand that larger formats don't need as fast an aperture as smaller formats. 35mm is a small format. 1/2.5" is miniscule..

The Panasonic FZ-20 that gives you decent f/2.8 constant can't sellas good as some new camera that gives you f/5.6 at the long end withhigh ISO stated because the marketing ppl don't know how to sell thebig aperture..

Make that f/5.6 sit in front of 35mm or even APS-C, and you are still at an advantage compared to the FZ-20..

And the FZ-30, at f/3.7 max aperture at the long end, isn't at much of a disadvantage compared to the f/2.8 constant of the FZ-20. The FZ-20 uses a 1/2.5" sensor, the FZ-30 (and 50) 1/1.8"..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #66

Nickleback wrote:.

You can also do it with shutter speed. Exposure has 3 variables..

Of course..

Then why concentrate on just one: aperture. That's exactly what youare doing by insisting on the same aperture ratio for "equivalence"..

Because we always have no choice for shuttle speed. We always need to set the shuttle speed first for most of the case and use the other 2 to adjust the exposure..

For shooting handheld, we need about 1/(focal length), if zoom in to 300mm, we need 1/300s. In many situation like this, we are limited to shooting at sunny day if we don't have external flash..

The above is the lower limit for handheld (although we can use tripod)..

For shooting moving subject, this get even worst if we want to freeze it motion..

Don't use the larger sensor advantage..

Why not use the larger sensor advantage? You paid for it, use it..

Ya, if you have paid for it, use it. But the OP would like to know how much advantage he can get for upgrading from APS-C to 35mm, hence, the explaining here..

Also, using amount of light go into the camera is not good way to link to quality, it would be better to use the amount of light fall on the sensor as below:.

If you use a same 200mm f/2.8 lens (design for full-frame) on both full-frame and 1.8x cropped, set at same shutter speed, the amount of light entering both camera is the same. However, the amount of the light CAPTURE by the sensor is different. Smaller sensor capture less light due to the cropped. The light that is fall outside the FOV of the 1.8x cropped sensor will be wasted...

Comment #67

Nickleback wrote:.

Circle of confusion (CoC) (in simple terms, the size of the largestdot on the sensor/film that appears sharp when enlarged) will need tobe smaller on the smaller sensor, because you are enlarging more forfinal output. Depth of field at the same aperture ratio will belarger on the smaller sensor too, due to smaller CoC and smalleraperture diameter..

The DoF will be larger on the smaller sensor camera, since the focal length will be shorter (not because the CoC is smaller) to get the same framing..

If all things are equal (focal length, subject distance, f-stop), a smaller CoC will give you *less* DoF, not more...

Comment #68

Nickleback wrote:.

If you want convenient, just stick the camera in full auto and itwill work out the details regardless of the max aperture of the lens..

Seems like you still don't understand. If you don't want convenient, don't use f-stop to talk about aperture. Use aperture diameter instead..

Same exposure does not require same aperture ratio..

No, with same shuttle speed, same aperture ratio (you mean f-stop?), and same ISO rating, you get the same exposure. Please get the meaning of exposure correct. Old photographers define all those f-stop, ISO rating such that they can easily know the exposure before shooting. They don't want to waste their film..

Least people care about same DOF and same noise performance, thus wedon't talk about equivalent in this context..

So you'd prefer to talk about non-equivalent equivalence?.

If everything is the same, why must we use "35mm equivalent"? FOV and exposure is something we can see directly when see a photo. DOF is not usually. And noise? Can be seen only if you do enlargement. Hence, for convenient sake, we tell other that this is 50mm (35mm-equivalent) and people will directly understand how the FOV will turn out. Or you want to tell him this is 8.33mm using on 1/2.5" sensor?.

Many of these equivalent things is set by the old photographers fortheir own convenient, not the marketers..

Old photographers understand that larger formats don't need as fastan aperture as smaller formats. 35mm is a small format. 1/2.5" isminiscule..

Yes, because they can "crank the ISO" by using very high ISO rating film..

The Panasonic FZ-20 that gives you decent f/2.8 constant can't sellas good as some new camera that gives you f/5.6 at the long end withhigh ISO stated because the marketing ppl don't know how to sell thebig aperture..

Make that f/5.6 sit in front of 35mm or even APS-C, and you are stillat an advantage compared to the FZ-20..

And the FZ-30, at f/3.7 max aperture at the long end, isn't at muchof a disadvantage compared to the f/2.8 constant of the FZ-20. TheFZ-20 uses a 1/2.5" sensor, the FZ-30 (and 50) 1/1.8"..

Again, I ask you not to compare with different sensor. It is not fair. FZ-20 with f/2.8 but 1/2.5" of course will have more noise than APS-C with f/5.6..

But FZ-20 f/2.8 1/2.5" at ISO 400 is much better than other with f/4 1/2.5" at ISO 800...

Comment #69

Skylark_khur wrote:.

Nickleback wrote:.

You can also do it with shutter speed. Exposure has 3 variables..

Of course..

Then why concentrate on just one: aperture. That's exactly what youare doing by insisting on the same aperture ratio for "equivalence"..

Because we always have no choice for shuttle speed..

You have lots of choice for shutter speed, aperture and ISO. In fact more choice on a larger sensor..

We always needto set the shuttle speed first for most of the case and use the other2 to adjust the exposure..

Usually a photographer picks which one of the 3 variables is most important, then sets the others to make it work. If you find shutter speed most important, set it and adjust aperture and ISO. Or let the camera do it, that's what shutter priority mode is for..

For shooting handheld, we need about 1/(focal length).

Roughly, and thats 1/35mm equivalent focal length. Unless of course you have IS and you can shoot at 4, 8 or even 16 over equivalent focal length..

If zoom in to300mm, we need 1/300s. In many situation like this, we are limitedto shooting at sunny day if we don't have external flash..

Not on a DSLR that can shoot clean ISO 3200!.

For shooting moving subject, this get even worst if we want to freezeit motion..

For long telephoto shots without IS, camera shake is typically the limiting factor..

Don't use the larger sensor advantage..

Why not use the larger sensor advantage? You paid for it, use it..

Ya, if you have paid for it, use it. But the OP would like to knowhow much advantage he can get for upgrading from APS-C to 35mm,hence, the explaining here..

A lot. Even with a slower lens. And even more if he chooses a faster lens..

Also, using amount of light go into the camera is not good way tolink to quality, it would be better to use the amount of light fallon the sensor.

You are arguing semantics. If you really want to get into it, a lot of the light going into a telephoto lens hits the inside of the lens barrel. My whole point was that at the same aperture ratio, a larger sensor gets more light. And you seem to agree with this below, but don't believe it when it comes to equivalence..

If you use a same 200mm f/2.8 lens (design for full-frame) on bothfull-frame and 1.8x cropped, set at same shutter speed, the amount oflight entering both camera is the same. However, the amount of thelight CAPTURE by the sensor is different..

That's precisely what I'm saying..

The same could be said of the light wasted going into a 72mm f/2.8 lens on a 1/2.5" camera. If the lens barrel were not in the way it would have lit up a lot more area. Go take a look at any large format lens and tell me what is different..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #70

Skylark_khur wrote:.

Nickleback wrote:.

If you want convenient, just stick the camera in full auto and itwill work out the details regardless of the max aperture of the lens..

Seems like you still don't understand. If you don't want convenient,don't use f-stop to talk about aperture. Use aperture diameterinstead..

Seems like you don't understand that you've got 3 variables to play with. You like to forget ISO when it is convenient for you to do so..

Same exposure does not require same aperture ratio..

No.

Yes. You've got 3 variables to play with, use them.

With same shuttle speed, same aperture ratio (you mean f-stop?),and same ISO rating, you get the same exposure..

Correct. You can also get the same exposure with same shutter speed, different aperture and different ISO..

Please get the meaning of exposure correct..

I think you need to brush up on this..

Old photographers define all thosef-stop, ISO rating such that they can easily know the exposure beforeshooting. They don't want to waste their film..

Old photographers understand this 3-way relationship. And we did waste film. The mantra was "film is cheap". If you don't believe it, you'll be too conservative, not experiment, and miss shots..

If everything is the same, why must we use "35mm equivalent"?.

Because marketing loves it..

FOV and exposure is something we can see directly when see a photo..

Exposure is 3 variables, you can shoot 1/100 f/4 ISO 100 or 1/400 f/2.8 ISO 200. Same exposure..

DOF is not usually..

You can't see DOF in a photo? That's very odd..

And noise? Can be seen only if you do enlargement..

Everything you see is an enlargement, unless you are contact printing..

Yes, because they can "crank the ISO" by using very high ISO ratingfilm..

Higher ISO film is grainier and doesn't enlarge as well. You'd know this if you shot and printed film..

Again, I ask you not to compare with different sensor. It is notfair..

It's not fair that larger sensors confer certain advantages? That's an odd way of looking at things..

But FZ-20 f/2.8 1/2.5" at ISO 400 is much better than other with f/41/2.5" at ISO 800..

FZ-30 doesn't use a 1/2.5" sensor. The 1/1.8"sensor it uses is larger than 1/2.5"..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #71

Dave_s93 wrote:.

If all things are equal (focal length, subject distance, f-stop), asmaller CoC will give you *less* DoF, not more..

Correct, thanks for catching that..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #72

You are arguing semantics. If you really want to get into it, a lot of the light going into a telephoto lens hits the inside of the lens barrel. My whole point was that at the same aperture ratio, a larger sensor gets more light. And you seem to agree with this below, but don't believe it when it comes to equivalence.<<<<<.

Nickelback:.

There seems to be a misconception pervading your posts that needs to be corrected. What is true is that for the same aperture ratio (FL/D) all lenses project the same amount of light PER UNIT AREA onto the sensing surface, regardless of the overall size of that surface. Large sensors have a noise advantage ONLY because the photo-sensing elements ("pixels") are spread over a wider area, and thus each pixel has more light-gathering area. This is not a characteristic of the lens..

What is also worth noting is that if a larger sensor had more pixels crammed onto it so that the pixel pitch (quantity per unit area) were the same as that of the smaller sensor, the noise advantage would disappear..

Davehttp://www.pbase.com/dsjtecserv..

Comment #73

Skylark_khur wrote:.

For shooting handheld, we need about 1/(focal length), if zoom in to300mm, we need 1/300s. In many situation like this, we are limitedto shooting at sunny day if we don't have external flash..

Assuming this to be a reliable maxim - all other factors being equal, let me ask another question. Since I will be using a 300mm lens on my A200, it will have an equivalent FL of 450mm. Will the formula for a steady shot still be 1/300 or will it become 1/450?.

Ralph..

Comment #74

Kd6vm wrote:.

Skylark_khur wrote:.

For shooting handheld, we need about 1/(focal length), if zoom in to300mm, we need 1/300s. In many situation like this, we are limitedto shooting at sunny day if we don't have external flash..

Assuming this to be a reliable maxim - all other factors being equal,let me ask another question. Since I will be using a 300mm lens onmy A200, it will have an equivalent FL of 450mm. Will the formulafor a steady shot still be 1/300 or will it become 1/450?.

Ralph.

Yes, that will be the rule of thumb. You will learn to adjust this based on your experience, the steadiness of your hands, and the effect of any IS. It is probably time for you to go out and start gaining that experience..

Davehttp://www.pbase.com/dsjtecserv..

Comment #75

Dsjtecserv wrote:.

Yes, that will be the rule of thumb. You will learn to adjust thisbased on your experience, the steadiness of your hands, and theeffect of any IS. It is probably time for you to go out and startgaining that experience..

Dave.

1/300 or 1/450?..

Comment #76

Kd6vm wrote:.

Dsjtecserv wrote:.

Yes, that will be the rule of thumb. You will learn to adjust thisbased on your experience, the steadiness of your hands, and theeffect of any IS. It is probably time for you to go out and startgaining that experience..

Dave.

1/300 or 1/450?.

1/450More generally, use the 35mm equivalent focal length..

Regards,Peter..

Comment #77

Sherwoodpete wrote:.

1/450More generally, use the 35mm equivalent focal length..

Thanks!Ralph..

Comment #78

Nickleback wrote:.

Because we always have no choice for shuttle speed..

You have lots of choice for shutter speed, aperture and ISO. In factmore choice on a larger sensor..

I have explained why we USUALLY (NOT ALWAYS) have no choice..

We always needto set the shuttle speed first for most of the case and use the other2 to adjust the exposure..

Usually a photographer picks which one of the 3 variables is mostimportant, then sets the others to make it work. If you find shutterspeed most important, set it and adjust aperture and ISO. Or let thecamera do it, that's what shutter priority mode is for..

Yes. But among the 3, shutter speed is most of the time the priority due to hand-shake and moving object..

For shooting handheld, we need about 1/(focal length).

Roughly, and thats 1/35mm equivalent focal length. Unless of courseyou have IS and you can shoot at 4, 8 or even 16 over equivalentfocal length..

Oh, I forget to mention equivalent here. At least your equivalent is same as my equivalent here..

If zoom in to300mm, we need 1/300s. In many situation like this, we are limitedto shooting at sunny day if we don't have external flash..

Not on a DSLR that can shoot clean ISO 3200!.

Yes, DSLR usually can get clean shot at ISO 3200, that's why we pay the price to get it..

For shooting moving subject, this get even worst if we want to freezeit motion..

For long telephoto shots without IS, camera shake is typically thelimiting factor..

Yes, camera shake is typically the limiting factor. But when you want to freeze a flying birds or moving cars, you need even faster..

Don't use the larger sensor advantage..

Why not use the larger sensor advantage? You paid for it, use it..

Ya, if you have paid for it, use it. But the OP would like to knowhow much advantage he can get for upgrading from APS-C to 35mm,hence, the explaining here..

A lot. Even with a slower lens. And even more if he chooses afaster lens..

Of course, if not why pay the price?.

Also, using amount of light go into the camera is not good way tolink to quality, it would be better to use the amount of light fallon the sensor.

You are arguing semantics. If you really want to get into it, a lotof the light going into a telephoto lens hits the inside of the lensbarrel. My whole point was that at the same aperture ratio, a largersensor gets more light. And you seem to agree with this below, butdon't believe it when it comes to equivalence..

You don't get my meaning here, the same amount of light is entering camera this time. But not all light is captured by the 1.8x sensor...

Comment #79

Dsjtecserv wrote:.

You are arguing semantics. If you really want to get into it, a lotof the light going into a telephoto lens hits the inside of the lensbarrel. My whole point was that at the same aperture ratio, a largersensor gets more light. And you seem to agree with this below, butdon't believe it when it comes to equivalence.<<<<.

Nickelback:.

There seems to be a misconception pervading your posts that needs tobe corrected. What is true is that for the same aperture ratio (FL/D)all lenses project the same amount of light PER UNIT AREA onto thesensing surface, regardless of the overall size of that surface.Large sensors have a noise advantage ONLY because the photo-sensingelements ("pixels") are spread over a wider area, and thus each pixelhas more light-gathering area. This is not a characteristic of thelens..

What is also worth noting is that if a larger sensor had more pixelscrammed onto it so that the pixel pitch (quantity per unit area) werethe same as that of the smaller sensor, the noise advantage woulddisappear..

Davehttp://www.pbase.com/dsjtecserv.

Thanks for being the "referee" here. I'm tired explaining and arguing with him..

Also, sorry to Original Poster if I'm bombarding your thread...

Comment #80

Skylark_khur wrote:.

Also, sorry to Original Poster if I'm bombarding your thread..

Don't be sorry. It has been a learning experience for all. Just goes to show that these optics questions involve many issues that can't be easily explained. Lots of physics involved and lots of speculation. Enjoyed it..

Ralph..

Comment #81

Nickleback wrote:.

Seems like you don't understand that you've got 3 variables to playwith. You like to forget ISO when it is convenient for you to do so..

I always understand this, just that you don't understand what I'm trying to tell you..

Same exposure does not require same aperture ratio..

No.

Yes. You've got 3 variables to play with, use them.

With same shuttle speed, same aperture ratio (you mean f-stop?),and same ISO rating, you get the same exposure..

Correct. You can also get the same exposure with same shutter speed,different aperture and different ISO..

Of course. I repeat this of course many times..

Please get the meaning of exposure correct..

I think you need to brush up on this..

No need, thanks..

Old photographers define all thosef-stop, ISO rating such that they can easily know the exposure beforeshooting. They don't want to waste their film..

Old photographers understand this 3-way relationship. And we didwaste film. The mantra was "film is cheap". If you don't believeit, you'll be too conservative, not experiment, and miss shots..

Large formats film is expensive. 35mm film is still more expensive than digital..

If everything is the same, why must we use "35mm equivalent"?.

Because marketing loves it..

Again, not because marketing. Because the user would like to conveniently know the FOV..

FOV and exposure is something we can see directly when see a photo..

Exposure is 3 variables, you can shoot 1/100 f/4 ISO 100 or 1/400f/2.8 ISO 200. Same exposure..

Of course (repeated again), but this is not I'm telling you. I'm telling you by seeing a photo, we can directly see the FOV, and we can directly know it is underexposed, overexposed or well-exposed..

DOF is not usually..

You can't see DOF in a photo? That's very odd..

As I said, it is USUALLY (NOT ALWAYS). If you used 300mm (35-equivalent) and 300mm (real) with same aperture, of course they have different DOF. But if your focus distance is beyond the hyperfocal distance of both lens setting, you get depth up to infinity. Although the near limit is different, it is hardly noticeable..

Again I repeat - NOT ALWAYS, but at least it is harder to see than FOV and exposure..

And noise? Can be seen only if you do enlargement..

Everything you see is an enlargement, unless you are contact printing..

Ok, you caught my wording flaw here. I mean big enlargement..

Yes, because they can "crank the ISO" by using very high ISO ratingfilm..

Higher ISO film is grainier and doesn't enlarge as well. You'd knowthis if you shot and printed film..

Yes, but you are telling me large formats, more grain is acceptable here than 35mm as you don't do as much enlargement for printing in same size..

Again, I ask you not to compare with different sensor. It is notfair..

It's not fair that larger sensors confer certain advantages? That'san odd way of looking at things..

But FZ-20 f/2.8 1/2.5" at ISO 400 is much better than other with f/41/2.5" at ISO 800..

FZ-30 doesn't use a 1/2.5" sensor. The 1/1.8"sensor it uses islarger than 1/2.5"..

Again for all this, of course larger sensor has advantage in term of noise performance (repeated myself again). But when we are comparing a thing, we need to keep other factors same. You are trying to compare all things at once..

Also, when did I tell you FZ-30 use 1/2.5"? I just tell you OTHER. True, FZ-30 use 1/1.8"...

Comment #82

Kd6vm wrote:.

Don't be sorry. It has been a learning experience for all. Justgoes to show that these optics questions involve many issues thatcan't be easily explained. Lots of physics involved and lots ofspeculation. Enjoyed it..

Ha, I did strengthen a lot of my concept when explaining. Ya, another thing I would like to add on to what dsjtecserv and sherwoodpete said about the rule of thumb..

If your lens have Image Stabilizer, you can stop down the shutter speed a bit. For example, if using the rule of thumb you need 1/300s, you can get steady shot at 1/150s, or even 1/75s with good IS...

Comment #83

Skylark_khur wrote:.

But when we are comparinga thing, we need to keep other factors same..

Nonsense. These "things" are related. Changing one without the other simply leads to false comparisons..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #84

Skylark_khur wrote:.

For example, if using the rule of thumb you need1/300s, you can get steady shot at 1/150s, or even 1/75s with good IS..

1/300 to 1/75 is only 2 stops. Good IS will give you 3 or 4..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #85

Skylark_khur wrote:.

Nickleback wrote:.

The mantra was "film is cheap". If you don't believeit, you'll be too conservative, not experiment, and miss shots..

Large formats film is expensive. 35mm film is still more expensivethan digital..

You don't need to tell me that. But film photographers (including me) had to delude ourselves so that we would take pictures without fear of what it all costs..

Exposure is 3 variables, you can shoot 1/100 f/4 ISO 100 or 1/400f/2.8 ISO 200. Same exposure..

Of course (repeated again), but this is not I'm telling you. I'mtelling you by seeing a photo, we can directly see the FOV, and wecan directly know it is underexposed, overexposed or well-exposed..

Can you tell if a photo was shot at 1/500 f/3.5 ISO 100 or 1/500 f/7 ISO 400? Same exposure..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #86

Nickleback wrote:.

Skylark_khur wrote:.

For example, if using the rule of thumb you need1/300s, you can get steady shot at 1/150s, or even 1/75s with good IS..

1/300 to 1/75 is only 2 stops. Good IS will give you 3 or 4..

Believe me, I am looking forward to that capability. I was able to shoot handheld 432mm shots with the Canon S3, which claimed only about 2 stops benefit with their in-lens stabilization. I should have no problem with the equiv. zoom on the Sony A200 with the sensor-shift. At least Sony claims up to 3.5 stops. We'll soon see..

Ralph..

Comment #87

Nickleback wrote:.

Skylark_khur wrote:.

But when we are comparinga thing, we need to keep other factors same..

Nonsense. These "things" are related. Changing one without theother simply leads to false comparisons..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed.

You are the one trying to be nonsense..

For example, when we are comparing whether f/2.8 ISO100 or f/5.6 ISO400 is better, of course we would like to compare it on the same sensor..

But you always just trying to bring in the bigger sensor advantage by saying f/5.6 ISO400 on DSLR is better than f/2.8 ISO100 on 1/2.5"..

What a nonsense claim that everybody will agree..

It is a very common sense that when you comparing 2 things, you must compare it with all others RELATED things fixed...

Comment #88

Nickleback wrote:.

Skylark_khur wrote:.

For example, if using the rule of thumb you need1/300s, you can get steady shot at 1/150s, or even 1/75s with good IS..

1/300 to 1/75 is only 2 stops. Good IS will give you 3 or 4..

That's VERY good IS. I wouldn't risk giving this suggestion that later people told me their picture is blurred because of hand shaking..

And this is just a general suggestion, steady hand or leaning against something can give you some extra stop as well..

And don't believe too much in marketing as you said... Claims about getting extra 4 stop in telephoto just from IS is not necessary true...

Comment #89

Skylark_khur wrote:.

But you always just trying to bring in the bigger sensor advantage bysaying f/5.6 ISO400 on DSLR is better than f/2.8 ISO100 on 1/2.5"..

So there is no bigger sensor advantage? News to me..

What a nonsense claim that everybody will agree..

You disagree? Any evidence to back it up?.

It is a very common sense that when you comparing 2 things, you mustcompare it with all others RELATED things fixed..

It's common sense when comparing things to make the comparison... comparable..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #90

Nickleback wrote:.

You don't need to tell me that. But film photographers (including me)had to delude ourselves so that we would take pictures without fearof what it all costs..

Ok, fair philosophy here. You can learn more without the fear. But when get into real action, it is better you can visualize what the result will end up or you will miss shot. Great moment for shots not always come, you can't ask the straying cat to stay there, you can't ask the bird to make the same flying action. You possibly can ask your friend to pose twice, but not ten times..

Exposure is 3 variables, you can shoot 1/100 f/4 ISO 100 or 1/400f/2.8 ISO 200. Same exposure..

Of course (repeated again), but this is not I'm telling you. I'mtelling you by seeing a photo, we can directly see the FOV, and wecan directly know it is underexposed, overexposed or well-exposed..

Can you tell if a photo was shot at 1/500 f/3.5 ISO 100 or 1/500 f/7ISO 400? Same exposure..

Not all the exact information in ABSOLUTE setting, but I can tell you their RELATIVE setting..

(1) - If the focus is beyond hyperfocal distance for both setting, and everything is beyond the focus distance > No. Because I differentiate the DOF clearly..

(2) - If same as (1) but there is a not-in-focus near object, I can tell you which was shot with larger aperture..

(3) - If the focused subject is between hyperfocal distance of either one or both, we can tell you which was shot with larger aperture..

(4) - If there is some motion in the shot, we can roughly tell you the shuttle speed used..

(5) - By seeing an uncropped photo, we can roughly tell the "35mm-equivalent" focal length, but not the real focal length if you didn't tell me the camera sensor size..

(6) - If you tell me this was shot with same camera and we do big enlargement of the shots, we can tell you which used higher ISO..

Finally, if you gave me the reading from light meter when taking the shot, I can tell you even more things..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed.

This is the fear to expose your film by mistake, and also the fear when thinking that what if the results do not turn out as we think it should. But the photographer that know what he is doing in real action will not have as much fear...

Comment #91

Nickleback wrote:.

Skylark_khur wrote:.

But you always just trying to bring in the bigger sensor advantage bysaying f/5.6 ISO400 on DSLR is better than f/2.8 ISO100 on 1/2.5"..

So there is no bigger sensor advantage? News to me..

I have repeatedly said the bigger sensor of course have advantage. And it is this advantage that make the comparison unfair..

What a nonsense claim that everybody will agree..

You disagree? Any evidence to back it up?.

I don't know what you mean... You can't get any mistake from this sentence of mine?.

It is a very common sense that when you comparing 2 things, you mustcompare it with all others RELATED things fixed..

It's common sense when comparing things to make the comparison...comparable..

What a meaningless sentence here..

Looks like you still don't know how to make fair comparason of things..

When there are 5 factors (let call it A, B, C, D, E) that affect the outcome. If we would like to compare whether A or B affect the outcome more, we need to keep C, D and E the same...

Comment #92

Skylark_khur wrote:.

Nickleback wrote:.

Skylark_khur wrote:.

But you always just trying to bring in the bigger sensor advantage bysaying f/5.6 ISO400 on DSLR is better than f/2.8 ISO100 on 1/2.5"..

So there is no bigger sensor advantage? News to me..

I have repeatedly said the bigger sensor of course have advantage.And it is this advantage that make the comparison unfair..

It's unfair to consider an advantage when making a comparison? You've already done it by using equivalent focal length. You are taking into account the advantage of the smaller sensor, namely that you can get the same field of view with a shorter focal length..

What a nonsense claim that everybody will agree..

You disagree? Any evidence to back it up?.

I don't know what you mean... You can't get any mistake from thissentence of mine?.

Here's the quote:.

But you always just trying to bring in the bigger sensor advantage by sayingf/5.6 ISO400 on DSLR is better than f/2.8 ISO100 on 1/2.5"..

What a nonsense claim that everybody will agree..

So you think that f/5.6 ISO 400 on a 35mm DSLR is not better than f/2.8 ISO 100 on 1/2.5"? Got any evidence to back this up?.

Looks like you still don't know how to make fair comparason of things.When there are 5 factors (let call it A, B, C, D, E) that affect theoutcome. If we would like to compare whether A or B affect theoutcome more, we need to keep C, D and E the same..

The problem with your interpretation is that, in this case, A & B are directly related. Focal length equivalence and aperture ratio equivalence are two sides of the same coin. You are choosing one side and disregarding the other. That's disingenuous at best..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #93

Nickleback wrote:.

Skylark_khur wrote:.

Nickleback wrote:.

Skylark_khur wrote:.

But you always just trying to bring in the bigger sensor advantage bysaying f/5.6 ISO400 on DSLR is better than f/2.8 ISO100 on 1/2.5"..

So there is no bigger sensor advantage? News to me..

I have repeatedly said the bigger sensor of course have advantage.And it is this advantage that make the comparison unfair..

It's unfair to consider an advantage when making a comparison?You've already done it by using equivalent focal length. You aretaking into account the advantage of the smaller sensor, namely thatyou can get the same field of view with a shorter focal length..

When did I taking into account the advantage of the smaller sensor when I said f/2.8 ISO100 is better than f/5.6 ISO400?.

With the same sensor, same shuttle speed, you get the same exposure here. But not the same DOF of course.But the noise of the first is lower than the second..

Then you bring in the unfair bigger sensor advantage by saying:f/5.6 ISO400 on DSLR is cleaner than f/2.8 ISO100 on 1/2.5".

Which I have told you I agree it MANY times, but this is senseless comparison when we just want to compare whether stopping up aperture or stopping up ISO is better..

The factors that we would like to compare now is F-STOP and ISO. Others factors - SHUTTLE SPEED (which you always bring up) and BIGGER SENSOR should be kept the same..

What a nonsense claim that everybody will agree..

You disagree? Any evidence to back it up?.

I don't know what you mean... You can't get any mistake from thissentence of mine?.

Here's the quote:.

But you always just trying to bring in the bigger sensor advantage by sayingf/5.6 ISO400 on DSLR is better than f/2.8 ISO100 on 1/2.5"..

What a nonsense claim that everybody will agree..

So you think that f/5.6 ISO 400 on a 35mm DSLR is not better thanf/2.8 ISO 100 on 1/2.5"? Got any evidence to back this up?.

Did I said that bigger sensor have no advantage in this sentence? I just ask you not to put this advantage to disturb the 2 things that we are comparing now > ISO and F-STOP..

I repeated many times that bigger sensor of course have advantages. You seems like arguing for the sake of arguing by claiming that I "disagree bigger sensor have advantages" when I never said so..

I repeat myself 10 times here:Yes, bigger sensor have advantages, if not we won't pay the price.Yes, bigger sensor have advantages, if not we won't pay the price.Yes, bigger sensor have advantages, if not we won't pay the price.Yes, bigger sensor have advantages, if not we won't pay the price.Yes, bigger sensor have advantages, if not we won't pay the price.Yes, bigger sensor have advantages, if not we won't pay the price.Yes, bigger sensor have advantages, if not we won't pay the price.Yes, bigger sensor have advantages, if not we won't pay the price.Yes, bigger sensor have advantages, if not we won't pay the price.Yes, bigger sensor have advantages, if not we won't pay the price..

Looks like you still don't know how to make fair comparason of things.When there are 5 factors (let call it A, B, C, D, E) that affect theoutcome. If we would like to compare whether A or B affect theoutcome more, we need to keep C, D and E the same..

The problem with your interpretation is that, in this case, A & B aredirectly related. Focal length equivalence and aperture ratioequivalence are two sides of the same coin. You are choosing oneside and disregarding the other. That's disingenuous at best..

I have explained how to compare things many times. Wouldn't want to repeat it again...

Comment #94

Skylark_khur wrote:.

Nickleback wrote:.

Can you tell if a photo was shot at 1/500 f/3.5 ISO 100 or 1/500 f/7ISO 400? Same exposure..

Not all the exact information in ABSOLUTE setting, but I can tell youtheir RELATIVE setting..

(1) - If the focus is beyond hyperfocal distance for both setting,and everything is beyond the focus distance > No. Because Idifferentiate the DOF clearly..

(2) - If same as (1) but there is a not-in-focus near object, I cantell you which was shot with larger aperture..

(3) - If the focused subject is between hyperfocal distance of eitherone or both, we can tell you which was shot with larger aperture..

(4) - If there is some motion in the shot, we can roughly tell youthe shuttle speed used..

(5) - By seeing an uncropped photo, we can roughly tell the"35mm-equivalent" focal length, but not the real focal length if youdidn't tell me the camera sensor size..

(6) - If you tell me this was shot with same camera and we do bigenlargement of the shots, we can tell you which used higher ISO..

Finally, if you gave me the reading from light meter when taking theshot, I can tell you even more things..

There are at least two meanings to exposure:.

As given by the light meter. Under, over, or right on. So I assume you agree 1/500 f/3.5 ISO 100 or 1/500 f/7 ISO 400 are the same exposure within this meaning, correct?.

A second meaning, which you allude to in your points above, is an image that looks the same in all ways..

Open two windows at http://www.dofmaster.com/dofjs.html. In one window, pick Canon Powershot S5 IS, then plug in 70mm, f/4, 100 feet. In the other windows pick Nikon D3, 420mm, f/25, 100 feet. You really should use f/24, but it's not available, so alternate between f/22 and f/25. f/24 in the middle of these two. Note in both focal length and aperture I'm using a factor of 6..

What do you see? I see the S5 IS has DOF between 89 and 114.2 feet. The D3 has the same (if you could pick f/24). So DOF is the same..

If you want blur (camera and/or subject) the same, you need to use the same shutter speed..

If you want the same shutter speed but need narrower aperture from the DSLR to match DOF, you need to pick a higher ISO. How much higher? Multiply by 6^2, or 36. So it's ISO 100 on the S5 IS vs ISO 3600 on the D3. How does the noise work out?.

Http://www.dpreview.com/reviews/canons5is/page7.asphttp://www.dpreview.com/reviews/NikonD3/page18.asp.

The S5 IS at ISO 100 has luminance noise at 2.5 (gray) and 2.0 (black), and RGB noise at 3.2. The D3 at ISO 3200 (sorry, ISO 3600 isn't available, and 3200 is 1/6 of a stop slower, 6400 is 5/6 of a stop faster) has luminance noise at 3.0 (gray) and 2.3 (black) and RGB noise at 3.2..

So I know what you are going to say. Ah Ha! The luminance noise on the S5 IS is lower, so the D3 at ISO 3200 isn't close to equivalent. I now invite you to look at the detail patches of the Queen's head. Notice the blurring of detail on the S5 IS, even at ISO 100? The ISO 80 crop has significantly more detail. The D3 maintains much more detail at ISO 3200, more than can be explained by 10mp vs 12mp. If you were to apply the same amount of NR to the D3 image, I'm guessing that the luminance noise will be about the same as the S5 IS, and detail the same too.

Look at what happens to the D300 luminance noise and detail at ISO 800, when NR kicks in on that camera..

So to get the same shutter speed, the same DOF, the same detail, and the same noise, when comparing a 1/2.5" camera to a 35mm camera, you need to use a focal length facotr of 6, aperture ratio factor of 6, and ISO ratio factor of 36. Then you are comparing apples to apples. Anything else and it is apples to oranges..

Good luck with your career in marketing..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #95

Seems like you are still comparing big and small sensors. I guess you never get what I was trying to tell. Ok, I try to rephrase my sentence by giving a scenario. What I'm trying to tell is just as simple as this:.

Using DSLR.

Now you have a DSLR on hand, mounted with a 50mm f/2.8 prime lens. Assuming you must shoot at a certain shuttle speed for some reasons. For your current ISO setting, your exposure meter tell you it is -2EV. To get the extra +2EV, you have 2 choices:.

1. Swap the lens with a 50mm f/1.4 prime lens. (stopping up aperture)2. Dial your ISO up 2 stops. (stopping up ISO).

If you need a cleaner image, you will need to go for the 1st choice..

Same things apply to P&S.

Now you have 2 cameras to choose. Both using the same type 1/2.5" sensors. The first one only let you to shoot at ISO800 max, but their largest aperture can go up to f/2.8. The second one is being advertised to let you shoot at maximum ISO1600 (what most marketers did), but they hide the fact that the largest aperture for their lens is f/4..

If you need a cleaner image, you should choose the 1st one..

That's all I'm trying to tell by saying "stopping up from f/5.6 to f/2.8 is better than stopping up from ISO100 to ISO400"..

Hope you are listening to me this time..

P/s: I won't be a good marketer as I still failed to convey my idea to you with so many posts...

Comment #96

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