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Crop factor/focal length mutiplyer - have i got this right
I am using the 400D. Am I right in syaing this has a crop factor of 1.6?.

If so, if I use let's say, a standard kit lens at 18mm and take picture with the 400D, the picture would appear to clsoer to the subject than if I had taken the picture with a Full Fram Camera (5D?) ? .

I think I understand the theory. A few questions though..

Does this mean the 400D has a smaller sensor?.

If so, why?.

And what are the practical implications in everyday photography?..

Comments (29)

Your camera has an APS-C sized sensor, which is 1.6 times smaller than the traditional 35mm film size..

Most lenses are designed for 35mm and their focal lengths are rated accordingly..

So 18mm on your APS-C sensor would be cropped by a factor of 1.6 and effectively deliver a field of view equivalent to 28.8mm on a 35mm camera..

Http://www.flickr.com/photos/shutterspy/..

Comment #1

Yes yes and Yes..

With a smaller sensor (22.2mm x 14.8mm vs 36mm x 24mm) you are effectively only capturing the middle area of the frame. You have to enlarge your image more to get the same print size and that makes the image appear like it is at a longer focal length than a 35mm frame would take..

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

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

See the first image is 35mm frame, second is APS-C. The bird isn't larger on the sensor, just the edges are lost because the sensor is smaller. When you enlarge the end result to view on your screen it will appear that the second image was taken with a lens 1.6 times the focal length..

Image source: http://www.dpreview.com/.../?/Glossary/Optical/Focal_Length_Multiplier_01.htm.

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

Comment #2

A quick answer is "Yes"..

THe next links will explain why..

Http://www.luminous-landscape.com/...ials/understanding-series/dslr-mag.shtml.

Http://www.kenrockwell.com/tech/crop-factor.htm.

Http://www.millhouse.nl/digitalcropfactorframe.html.

Http://en.wikipedia.org/wiki/Crop_factor.

It's one of those things that can really be a nice thing or a pain in the ....

I'm gonna have to sell some of this stuff so I can buy more stuff! Mummm, more stuff!..

Comment #3

If so, why?.

Smaller form factor, less materials cost=cheaper price and more accessability to John Q. Public to renew or take up a new hobby. Would you rather lug a brick around your neck all day or 1/2 a brick?.

And what are the practical implications in everyday photography?.

The + is more zoom for your $ vs. the FF equal.

The - is you lose on the short focal lengths and increased higher ISO noise vs. FF.

Steve..

Comment #4

Scoot4nat wrote:[snip].

I think I understand the theory. A few questions though..

Does this mean the 400D has a smaller sensor?.

Yes, it has a smaller sensor than a full frame DSLR. So do amost all non-professional DSLRs..

However, it is a much larger sensor than those used on compact digital cameras..

If so, why?.

Because it is very expensive to manufacture full frame size sensors. That is why the only full frame DSLRs are very expensive and mainly aimed at professionals..

And what are the practical implications in everyday photography?.

Very little. Most of the confusion arises around the effect of the crop factor on effective lens focal lengths. Focal lengths are important because they give you an indication of the effective magnification of the lens, and therefore what they are likely to be used for..

Chris R..

Comment #5

Scoot4nat wrote:.

And what are the practical implications in everyday photography?.

A crop sensor will frequently have more pixels per inch than a full frame sensor. This in turn yields higher resolution. So while the 1.6 crop factor isn't a focal length multiplier, the higher pixel density sort of is a focal length multiplier. This is advantages for shooting things at a distance like wildlife and sports..

But the bottom line is, a 200mm lens is a 200mm lens no matter what camera it is on. The only thing that really changes is the field of view. This is not the same as zooming in or out. Despite what I said about higher pixel density sensors, a lens will only resolve so much detail. You could have an old full frame camera and a newer one with higher pixel density and get the same effect - it really has nothing to do with sensor size..

Now that you've had everything explained and that we've thoroughly confused you, and let's say you go and buy a crop camera - don't even think about the crop factor. You don't need to know what your pic would look like on a full frame any more than someone shooting 35mm film needs to know what their pic would look like on a 4x5 medium format camera with the same focal length lens. Bottom line - understand the principal of crop factor, but don't give it a second thought..

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Even if you can't donate, please help spread the word...

Comment #6

Scoot4nat wrote:.

Does this mean the 400D has a smaller sensor?.

If so, why?.

It has a smaller sensor because it's based on the traditional DSLR (hey, it's been basically five years since the original Rebel brought DSLR photography to the masses, so DX cameras can be traditional). The traditional DSLR used the largest sensor that could be reasonably manufactured. Because these sensors were placed in bodies similar to 35mm SLRs and used 35mm SLR lenses, the classic 35mm focal lengths were used, hence an 18-55 lens is marked as an 18-55, as opposed to it's effective focal length of 28.8-88 in Canon and 27-82.5..

As costs have come down, FX sensors have been marketed in cameras such as athe 5D.

And what are the practical implications in everyday photography?.

Virtually nil. Though it does result in lots of debate on this and similar boards..

'Nice pen, bet you write good stories with it.'..

Comment #7

Depends on your definition of everyday photography..

It affects your calculations when you are working with Depth of field. you can't just tell the calculator that it is 28.8mm because of my crop factor. it is 18mm lens length (28.8 mm equal angle of view). it changes your circle of confusion..

Look in the glossary to bring yourself up to speed with DoF and focal length. grasp those concepts and you will know how it affects every day shooting..

Work is money,time is irreplaceable..

Comment #8

Scoot4nat wrote:.

If so, if I use let's say, a standard kit lens at 18mm and takepicture with the 400D, the picture would appear to clsoer to thesubject than if I had taken the picture with a Full Fram Camera (5D?)?.

It won't change the perspective. That depends on camera-subject distance. It will change the apparent magnification for field of view purposes, that 18mm lens will "act like"a 28.8mm lens on a 400D..

Does this mean the 400D has a smaller sensor?.

Yes, it is smaller than a 35mm negative..

If so, why?.

Cost. Large sensors are more expensive because of silicon area consumed, and because of the cost of discarding defective sensors. (This is two-fold: the larger the sensor, the greater the odds it will have a defect requiring it to be trashed, and the higher the loss involved in trashing it.).

And what are the practical implications in everyday photography?.

Cheaper telephoto. More expensive normal and wide angle. Somewhat greater depth of field (which may be a drawback), though the effect is not so strong as with compact digicams (and their tiny sensors)..

If you have a mix of crop-sensor and full-frame bodies that share a lens mount, sharing (full-frame) lenses is possible, but more "interesting" to manage than it would be if you had all crop-sensor bodies or all full-frame bodies...

Comment #9

Thank you for your explanations. I like to have an overall understanding of the workings of how these thngs......well work,for want of a better word!.

So in summary..

1. Perspective does not change..

2. It's really not importnat other than when using the focal length mulitiplyer(for depth of field????).

3. It's not to confuse people like me - simply due to cost..

4. I get more zoom..

5. But less wide angle .

6. Lens focal lengths are marked as a FF equivlant..

7. That includes EF-S lenses, despite them only being compatible with croppedsensors. (400D and 450D are 1.6? What about 30D 40D).

8. It as been stated that the smaller sensor effectively "cuts off" part of thepicture, due to field of view beingnarrowe; does this distort what I seethrough the viewfinder..

9. Cropped sensrs basically bring you a little closer to your subject. At 18mm ona 400D the subject will seem a lkittlke (or a lot) closer than alkl things thesame on a 5D?.

One last question, how is the focal lkength of a lkens calculated?(That may be the wrong term - what I mean ius he numbers lets say 18-55mm..

Something from memory tellks me it is the diustance from the sensor in the camera to the end of them lkes i,e. the glass. If thius is the case,m why is the 50mm 1.8 quite a bit shorter than the 18-55mm kit lens?.

Once agiun, thank you all!..

Comment #10

Scoot4nat wrote:.

Thank you for your explanations. I like to have an overallunderstanding of the workings of how these thngs......well work,forwant of a better word!.

3. It's not to confuse people like me - simply due to cost..

One more thing that is seldom mentioned. The size of lenses are reduced with a smaller sensor. As a result the lenses can be lighter and cheaper. The cost benefit is NOT because the sensor is hughly cheaper. It is because the glass is less expensive to produce. Camera companies make their $$ on glass not on bodies in the same way that printer company's make money on ink not on printers..

Optical glass goes for about $1,000 per Kg. Smaller lenses mean they can produce them cheaper and make more on the sale. Compare the size of a 300mm lens made for a Full Frame DSLR, APS-C DSLR and a 4/3 DSLR and then look at the size of the lens on super zoom point and shoot and you will see what I mean..

JimOlympus E-510 and a bunch of stuff to hang on it...

Comment #11

Scoot4nat wrote:.

6. Lens focal lengths are marked as a FF equivalent..

No. Interchageable lens f-length marked are actual f-lengths, NOT equvelants....

To get an idea of full frame equivalent framings....

(because you are used to using a full frame film camera and can recall the framings each f-length gave you with different subjects and distances).

.... then multiply your actual f-length by crop factor [1.6 in your case.].

If you are not familiar with full frame f-length/framings (see above) then for goodness sake don't bother getting familiar with *equivalents*, as you will be wasting your time and confusing yourself. Just get on with the business of using your camera, and learn how the different f-lengths frame on the camera you actually HAVE! Okay?.

7. That includes EF-S lenses, despite them only being compatible withcroppedsensors. (400D and 450D are 1.6? What about 30D 40D).

30D and 40D have slightly larger sensors... crop factor 1.5 by comparison with FF..

8. It as been stated that the smaller sensor effectively "cuts off"part of thepicture, due to field of view being narrowe; does this distort what I seethrough the viewfinder..

No. Not distorted. But in cheaper cameras like yours the view through the viewfinder is not of the whole image as it appears on sensor. Expect to find about 18% more around the edges than the viewfinder shows..

9. Cropped sensors basically bring you a little closer to yoursubject. At 18mm ona 400D the subject will seem a lkittlke (or a lot) closer than alklthings thesame on a 5D?.

No. Cropping doesn't "bring you closer". It just shows less around the edges of the shot, which is a different thing entirely..

One last question, how is the focal length of a lens calculated?(That may be the wrong term - what I mean ius he numbers lets say18-55mm..

F-length *used* to be the distance from the optical centre of the lens to the film/sensor when the lens was focused on infinity (moon and stars, say)..

So, a 50mm lens will be 50mm (2") from the film/sensor when it is imaging the sun, like a burning glass does on a dry leaf. [You can go out and try this on a sunny day... but please be careful not to set fire to Southern California!].

However, as lens construction was changed to 'teles-cope' long f-lengths into shorter, more convenient, physical tubes (tele-lenses), and short f-length lenses (wide-angles) were made physically longer (retro-focus) to allow sufficient room behind them for SLR's swing-up mirrors to be fitted.... and then zoom lenses were invented that could vary positioning of internal glass elements between BOTH the above types....

....(breath!)....

..... so the strict correlation between f-length and the distance from lens-to-sensor, has been lost. Nevertheless, the f-lengths DO maintain the same framing as the genuinely long, short, or normal f-length lenses used to show, and that is the important thing. .

Something from memory tellks me it is the diustance from the sensorin the camera to the end of them lkes i,e. the glass.If thius isthe case,m why is the 50mm 1.8 quite a bit shorter than the 18-55mmkit lens?.

Well spotted.... (but see above.)Regards,Baz..

Comment #12

Scoot4nat wrote:.

2. It's really not importnat other than when using the focal lengthmulitiplyer(for depth of field????).

The focal length multiplier is useful if you are accustomed to using absolute focal lengths to measure (magnification / field of view) on a 35mm camera, and you want to keep working in terms with which you're familar..

It's also useful if you want to compare lenses on cameras with different sensor sizes e.g., a Canon S2 IS superzoom and a Canon Digital Rebel EOS 400D..

If you're starting from scratch with a new DSLR system and you're using only a single sensor size, there's nothing wrong with learning what "wide", "normal", and "telephoto" mean in "native" terms from the start. (E.g., "normal" would mean a (50/1.6)mm focal length, so you just memorize that "normal" is a focal length around 30mm, instead of memorizing 50mm and repeatedly converting.).

6. Lens focal lengths are marked as a FF equivlant..

Focal lengths aren't actually sensor-size dependent..

The deal is that the magnification and field of view you get depend BOTH upon lens focal length AND upon sensor size. The reason that 35mm users got away with using just focal length to express magnification is that most rarely changed over to any other interchangeable lens format. So the "sensor size" remained a constant for all but a few medium format and large format users..

Now that there are different sensor sizes visible to the mass market, the "other shoe" has dropped..

7. That includes EF-S lenses, despite them only being compatible withcroppedsensors. (400D and 450D are 1.6? What about 30D 40D).

The EF-S lenses only project a light circle big enough to cover the APS-C sensor, and I believe Canon's design makes them mechanically incompatible with any full frame camera..

EOS 30D and 40D are also crop-sensor (1.6x) cameras..

There are/were some Canon 1.3x crop factor cameras, and there are some full frame ones (most are very expensive; the cheapest is the EOS 5D)..

8. It as been stated that the smaller sensor effectively "cuts off"part of thepicture, due to field of view beingnarrowe; does this distort what I seethrough the viewfinder..

The viewfinder will crop the image in the same way. However, the smaller sensor will mean that there is less light available for the viewfinder..

9. Cropped sensrs basically bring you a little closer to yoursubject. At 18mm ona 400D the subject will seem a lkittlke (or a lot) closer than alklthings thesame on a 5D?.

Here's where you would use the focal length multipler to convert one camera's settings into the other's units, so you can do an apples-to-apples comparison...

Comment #13

Baz.

What happens when people start reading, this pro is using a 1dsmIII with a 200mm lens. and the person is trying to get the same shot with their 400d and a zoom lens but every time they look at their lens they notice it is set at 125mm.....

Or the same guy reads that to take portraits that 85mm lens work well or work well. they set their lens to 85mm and what happens....

I thinkI thoughtI was..

Comment #14

Osymo wrote:.

Bazwhat happens when people start reading, this pro is using a 1dsmIIIwith a 200mm lens. and the person is trying to get the same shot withtheir 400d and a zoom lens but every time they look at their lensthey notice it is set at 125mm.....

Or the same guy reads that to take portraits that 85mm lens work wellor work well. they set their lens to 85mm and what happens....

Then they will find out pretty quickly that different sized sensors demand different focal lengths to get similarly framed pictures. This process is called "getting experience"... and there is no known substitute for it. Regards,Baz..

Comment #15

Osymo wrote:.

Look in the glossary to bring yourself up to speed with DoF and focallength. grasp those concepts and you will know how it affects everyday shooting..

Nope, I've had about 20 years dealing with DOF and focal length and compression in both 35mm and medium format so I'll pass on the glossary. But I suspect the difference in depth of field on a wide angle and ultra wide angle (or whatever category you choose to put 18 and 28 in), on a lens that doesn't go wider than F 3.5 would meet my definition of "virtually.".

If you notice a difference in the images you produce out in the field, that's great..

'Nice pen, bet you write good stories with it.'..

Comment #16

Good point. took me a while to come to an understanding.I thinkI thoughtI was..

Comment #17

Parrot.

That may be on the wide angle end ; it does start changing quickly when you start zooming. but yall are right, just start taking pictures..

OP, fill your card up with pictures, go home and get them into your computer. review them. are the fuzzy, are they dark are they bright, is the picture crowded, is it too open. next day fill your card up with pictures, get them onto your computer. review them. figure out what you don;t like about them.

Play with your camera settings while researching. someone suggests something, try it out with your camera. go to sleep. wake up. go to work, have your camera in your car at least.

Review, go online and search for image problems..

Do that for about a week and you will be on your way to making better photographs..

These guys are right. just go out and have some fun. all this math stuff is for the birds.(tweet,tweet)  it won't make a difference in your pictures..

I thinkI thoughtI was..

Comment #18

Maddogmd11 wrote:.

One more thing that is seldom mentioned. The size of lenses arereduced with a smaller sensor. As a result the lenses can be lighterand cheaper..

Not really. The only elements affected are the rear elements - which are the smallest to begin with..

Suppose you want a lens that is 200mm F2. Whether you design it for full frame or 1.6 crop (ie, Canon EF-S), the front element will still be 100mm in diamater and the cost and weight will be huge. The end result being that there really is no practical purpose to design a crop version of such a lens because any weight savings will be negligible, and the cost savings would be zero. Crop only lens design is only practical on the wide end..

Optical glass goes for about $1,000 per Kg. Smaller lenses mean theycan produce them cheaper and make more on the sale. Compare the sizeof a 300mm lens made for a Full Frame DSLR, APS-C DSLR and a 4/3 DSLRand then look at the size of the lens on super zoom point and shootand you will see what I mean..

That's because you're comparing a 300mm lens to a 60mm lens. A true 300mm lens on a P&S would be just as big as one for a DSLR. As a result a P&S with a 300mm 'equivalent' lens will only resolve as much detail as a 60mm on a DSLR...

Comment #19

Really,.

Then I guess that Olympus and Panisonic and Lieca have it all wrong. They really should make the 4/3 lenses largerr because they can't actually be the focal lengths that are stated..

Jim.

Olympus E-510 and a bunch of stuff to hang on it...

Comment #20

PhysicsIts only natural.

This is a good place to start..

Http://www.normankoren.com/Tutorials/MTF1A.html.

JimOlympus E-510 and a bunch of stuff to hang on it...

Comment #21

And yes, it is right. But I am also right that when I say a 200mm F2 lens is going to be huge no matter what camera it is put on - you simply can't alter the physics that aperture diameter is a function of focal length and f-stop. I am also correct in that you can't compare a full frame 300mm lens to a 300mm equivalent P&S because the lens on the P&S is really 60mm or thereabouts. Smaller lenses will benefit more - a 60mm F4 on a point and shoot could get away with a 15mm wide front element - that won't happen on a DSLR - so yes, you're point is valid. But with bigger and faster lenses, the laws of physics - ie front element sizes - dictates that such lenses will be more similar regardless of sensor size..

Maddogmd11 wrote:.

Really,.

Then I guess that Olympus and Panisonic and Lieca have it all wrong.They really should make the 4/3 lenses largerr because they can'tactually be the focal lengths that are stated..

Jim.

Olympus E-510 and a bunch of stuff to hang on it..

Some cool cats that can use your helphttp://www.wildlife-sanctuary.org.

Even if you can't donate, please help spread the word...

Comment #22

I can't speak about the P&S lenses because I've never really looked at them and except for some exceptions I think most of them, although I can't be sure, don't use high quality optical glass. I agree that you don't get to tiny just because you have a small sensor but you can make them smaller and in the view of some have to make them smaller and sharper as compared to a full frame lens..

So bottom line is I think we are both in agreement..

Later.

JimOlympus E-510 and a bunch of stuff to hang on it...

Comment #23

If manufacturers could make smaller sized big aperture lenses, why haven't they?.

For example:.

Olympus 300 2.8, 11.1 inches long and 7.2 pounds..

Nikon 300 2.8, 10.5 inches long and 6.3 pounds.

Canon 300 2.8, 9.9 inches long and 6 pounds.

Or.

Canon 200 2, 8.2 inches long 5.6 pounds.

Nikon 200 2, 8 inches long 6.4 pounds.

Olympus NA.

Of the three 300 2.8s, the Olympus is the largest and the heaviest and's for a 4/3 camera and the others are for FX sensor cameras? Oh yeah, it's also the most expensive..

Of similar value use cameras, the weight breaks down like this:.

Olympus E-3 28.7 ounces.

Nikon D300 29.2 ounces.

Canon 40D 26.1 ounces.

Good thing Nikon beefed up the D300 or the E-3 could have been the heaviest..

This does not reflect on the value/use of the 4/3 system. Olympus is doing some truly amazing things with it's E-4xx and E-5xx series cameras and I've seen some truly wonderful images come out of the E-3. (I bought a refurb E-500 to use with some old Leica R lenses so I believe in that system too).

For the lower and mid-level cameras, coupled with shorter focal length lenses and zooms, the size and weight advantage purported is legitimate. For the "flagship camera" and pro level gear, it ain't happening..

'Nice pen, bet you write good stories with it.'..

Comment #24

Scoot4nat wrote:.

Thank you for your explanations. I like to have an overallunderstanding of the workings of how these thngs......well work,forwant of a better word!.

So in summary..

1. Perspective does not change..

Yep.

2. It's really not importnat other than when using the focal lengthmulitiplyer(for depth of field????).

Not really understanding what you mean..

3. It's not to confuse people like me - simply due to cost..

What? sensor size? yes! Lens designation? no..

4. I get more zoom..

No, you get more telephoto. Zoom is the tele/wide ratio..

5. But less wide angle .

Yes..

6. Lens focal lengths are marked as a FF equivlant..

You got this wrong. The lens are marked with their REAL focal lenght. Which is not dependant on the sensor size. A 50mm lens is a 50mm lens is a 50mm lens .

However, the 50mm lens will act as a normal lens on film or full frame, as a medium telefoto on your APS sensor, as a wide angle on medium format and as a supertelefoto on a compact camera..

7. That includes EF-S lenses, despite them only being compatible withcroppedsensors. (400D and 450D are 1.6? What about 30D 40D).

Yep. 1.6..

8. It as been stated that the smaller sensor effectively "cuts off"part of thepicture, due to field of view beingnarrowe; does this distort what I seethrough the viewfinder..

No. What you see is what you see. You get in the viewfinder roughly what it will be captured. (however, in most consumer cameras, viewfinder does not cover the whole image, so you'll get slightly more).

9. Cropped sensrs basically bring you a little closer to yoursubject. At 18mm ona 400D the subject will seem a lkittlke (or a lot) closer than alklthings thesame on a 5D?.

No. It will seem exactly as far, however, you'll get less picture .

One last question, how is the focal lkength of a lkens calculated?(That may be the wrong term - what I mean ius he numbers lets say18-55mm..

The focal lenght of the lens is the distance from the lens center to the point where paralel light rays converge..

Something from memory tellks me it is the diustance from the sensorin the camera to the end of them lkes i,e. the glass. If thius isthe case,m why is the 50mm 1.8 quite a bit shorter than the 18-55mmkit lens?.

Nope, bad memory .

Once agiun, thank you all!.

You're welcome..

Comment #25

Devnull wrote:.

Scoot4nat wrote:.

Thank you for your explanations. I like to have an overallunderstanding of the workings of how these thngs......well work,forwant of a better word!.

So in summary..

1. Perspective does not change..

Yep.

2. It's really not importnat other than when using the focal lengthmulitiplyer(for depth of field????).

Not really understanding what you mean..

3. It's not to confuse people like me - simply due to cost..

What? sensor size? yes! Lens designation? no..

4. I get more zoom..

No, you get more telephoto. Zoom is the tele/wide ratio..

You only get more telephoto in the sense that the angle of view is narrower but you do not get more telephoto scene magnification. See BA baracas post of bird pictures and #9 below..

5. But less wide angle .

Yes..

6. Lens focal lengths are marked as a FF equivlant..

You got this wrong. The lens are marked with their REAL focal lenght.Which is not dependant on the sensor size. A 50mm lens is a 50mm lensis a 50mm lens .

However, the 50mm lens will act as a normal lens on film or fullframe, as a medium telefoto on your APS sensor, as a wide angle onmedium format and as a supertelefoto on a compact camera..

7. That includes EF-S lenses, despite them only being compatible withcroppedsensors. (400D and 450D are 1.6? What about 30D 40D).

Yep. 1.6..

8. It as been stated that the smaller sensor effectively "cuts off"part of thepicture, due to field of view beingnarrowe; does this distort what I seethrough the viewfinder..

No. What you see is what you see. You get in the viewfinder roughlywhat it will be captured. (however, in most consumer cameras,viewfinder does not cover the whole image, so you'll get slightlymore).

9. Cropped sensrs basically bring you a little closer to yoursubject. At 18mm ona 400D the subject will seem a lkittlke (or a lot) closer than alklthings thesame on a 5D?.

No. It will seem exactly as far, however, you'll get less picture .

One last question, how is the focal lkength of a lkens calculated?(That may be the wrong term - what I mean ius he numbers lets say18-55mm..

The focal lenght of the lens is the distance from the lens center tothe point where paralel light rays converge..

Something from memory tellks me it is the diustance from the sensorin the camera to the end of them lkes i,e. the glass. If thius isthe case,m why is the 50mm 1.8 quite a bit shorter than the 18-55mmkit lens?.

Nope, bad memory .

Once agiun, thank you all!.

You're welcome..

Comment #26

Devnull wrote:.

You got this wrong. The lens are marked with their REAL focal lenght.Which is not dependant on the sensor size. A 50mm lens is a 50mm lensis a 50mm lens .

There is a difference in the way DSLR lenses and P&S cameras are marketed. DSLR lenses are marked and marketed by their true focal length. P&S camera lenses are marked with their true focal length, but marketed with their 35mm equivalent...

Comment #27

Barrie Davis wrote:.

30D and 40D have slightly larger sensors... crop factor 1.5 bycomparison with FF..

The 40D's sensor is the same size as the 400D and 450D, 22.2mm wide, 1.622x. The 20D and 30D were 22.5mm wide, 1.600x. Nikon's are 23.6mm wide, 1.525x..

So, all the Canons get rounded to 1.6x, even though the 20D and 30D were very slightly larger. Nikon, Pentax and Sony are 1.5x...

Comment #28

Greg Nut wrote:.

Barrie Davis wrote:.

30D and 40D have slightly larger sensors... crop factor 1.5 bycomparison with FF..

The 40D's sensor is the same size as the 400D and 450D, 22.2mm wide,1.622x. The 20D and 30D were 22.5mm wide, 1.600x. Nikon's are23.6mm wide, 1.525x..

So, all the Canons get rounded to 1.6x, even though the 20D and 30Dwere very slightly larger. Nikon, Pentax and Sony are 1.5x..

No argument, Greg.I stand corrected, and hope my error didn't mislead anyone too much..

Thanks. Regards,Baz..

Comment #29

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This question was taken from a support group/message board and re-posted here so others can learn from it.

 

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