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focused object , blurry background
Hi all.

I am using canon SD800 IS , I would like your help with this small question:.

How do I take a picture that the main object is focused and everything around him is blurry..

Is this a special shooting mode?.

Tx..

Comments (28)

Yanivecp wrote:.

Hi all.

I am using canon SD800 IS , I would like your help with this smallquestion:.

How do I take a picture that the main object is focused andeverything around him is blurry..

Is this a special shooting mode?.

Tx.

With your camera, it will be very difficult to achieve (without going into detail). If you would like the details, I'd be happy to explain..

The best you can do is:.

1) Choose the largest aperture (smallest f-number, for example f/2.8 is a larger aperture than f/4, but f/2.8 is a smaller f-number; in this case you'd choose f/2.8 over f/4)..

2) Get as close to your subject as possible (without disturbing the setting you're looking for)..

3) Maximize the distance of anything behind the subject. For example, an ideal example of this is to shoot a coke can on a balcony, where you are standing on the balcony and the nearest thing off the balcony is 200ft away..

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 #1

Timskis6 wrote:.

The best you can do is:1) Choose the largest aperture (smallest f-number, for example f/2.8is a larger aperture than f/4, but f/2.8 is a smaller f-number; inthis case you'd choose f/2.8 over f/4).2) Get as close to your subject as possible (without disturbing thesetting you're looking for).3) Maximize the distance of anything behind the subject. Forexample, an ideal example of this is to shoot a coke can on abalcony, where you are standing on the balcony and the nearest thingoff the balcony is 200ft away..

4) Zoom in as much as possible or practical. A longer focal length (more zoom).

To the OP: You are looking for a shallow DOF (not Dad-of-four, but Depth of Field) Each of these 4 suggestions gives you a shallow DOF.The problem you will have is that there is a 5th factor - Sensor Size..

Your camera (and most P&S) have a SMALL sensor. All things being equal, a SMALLER sensor gives a LARGER DOF. Of course, you want a SMALLER DOF, so you would want a camera with a LARGER sensor. A P&S just cannot offer this.Warm regards,DOF..

Comment #2

Can I ask if I have control on the f-number for this camera , if so how do I do that?..

Comment #3

....you should check your manua, but I know that my first point and shoot camera did not have that capability to change f-stops..

I see that your camera has a digital macro shooting mode...have you tried that?LucyE- 510, 14-150 and 14-54 lens!U ZI owner!Olympus C30-20Zhttp://www.pbase.com/lucyFCAS Member #98, Oly Division'Photography is the art of seeing what others do not.'.

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

Comment #4

One simple method is a post shooting process. You make 2 layers in Photoshop or similar product and blur the top layer (radial, motion, gaussian blurs all work well) then layer mask or just 'erase' (not recommended but ok for a first attempt) on the top layer (with a soft brush) the area where you want the bottom layer (non blurred) to show through! Layer mask and the gradiant (normal first pull then screen or multiply to shape as needed) tool work best. Close cutting is another method...very advanced. Then flatten and save..

Hope this was understandable, it's a big topic but you can get a result this way if camera controls are limited...

Comment #5

Yanivecp wrote:.

Can I ask if I have control on the f-number for this camera , if sohow do I do that?.

It's in the creative modes - it's Av mode on the dial. Don't know if you have that control, but check...

Comment #6

Yanivecp wrote:.

Hi all.

I am using canon SD800 IS , I would like your help with this smallquestion:.

How do I take a picture that the main object is focused andeverything around him is blurry..

Is this a special shooting mode?.

The basics have been discussed in other replies, but they're not the whole story..

As others have said, the background will be more out of focus if it's further away from the subject..

I don't know your camera, but I'm sure it will have a portrait shooting mode that should open up the aperture to try to separate the subject from it's background as much as the camera can achieve..

That covers the short answer. If you want to understand better, then what follows is how it all really works..

Depth of field (DOF) is the range of sharp focus from near to far. Smaller DOF means the subject is isolated more and the foreground and background are blurred more, which is what you are after..

Because of your camera's small image sensor size (compared to DSLRs for example), the lens is small and the aperture (lens entrance pupil size - the 'hole' in the lens - not f-stop) is still quite small even at the widest aperture (smallest f-stop number)..

The aperture size (lens entrance pupil size) has a big influence on DOF, with larger (wider) apertures producing smaller DOF than smaller (narrower) apertures. Your camera is way more limited in providing a shallow DOF than a camera with a larger sensor like any DSLR..

If you keep the f-stop the same and change the focal length (FL) you're using, you change the aperture size. For the same f-stop at a longer FL, the aperture (entrance pupil) has to be bigger, resulting in a smaller DOF ... for the same focus (subject) distance..

There are three key DOF factors to consider with your camera..

1) Focus distance (distance to subject)..

The distance of the subject (that you focus on) affects the DOF. Focusing closer means a smaller (shallower) DOF. Focusing further away means a larger (deeper) DOF..

2) Aperture size..

This is a combination of the lens focal length and the f-stop (lens entrance pupil size equals the FL divided by the f-stop number). Here's where people often get confused. To frame your subject (what you focus on) the same at different lens FLs, you have to move your camera closer to or further from your subject (this also changes the image perspective, ie the relationship of the elements of the image to each other). The effect on DOF of the changing focus distance cancels out the effect on DOF on the changing aperture size due to the changing focal length for a given f-stop. In other words, if you keep the f-stop the same while changing FL and moving your camera to keep the subject framing the same, the DOF will stay the same..

You might conclude that from the DOF point of view it doesn't matter whether you frame from close or further away if you don't care about the perspective. It's not that simple. There are two more factors to take into account..

The first factor is that the smallest f-stop of our camera changes as you zoom in, with a smaller minimum f-stop possible at the wide end of the zoom range (shorter FL) and a larger minimum f-stop number available at the long end of the zoom range (longer FL)..

From what I've said so far, you might conclude that you're better off using a shorter FL from closer so you can use a smaller f-stop and achieve a smaller DOF than you could with a longer FL from further away with the larger f-stop, the f-stop being the deciding factor as the other factors cancel each other out. However, that brings into play the third consideration at the next point..

3) Perceived DOF..

In the end, the DOF numbers don't matter as much as how you perceive the image to look. If you think the background (and foreground) looks more blurred/out of focus and that's what you're after, then that's what matters..

For a given subject framing with your camera at the same f-stop, changing FL while adjusting distance to keep the subject framing the same will mean the same DOF, as already covered. However, longer FLs in this situation will make the background elements larger in the image frame with respect to the size of the subject (distance compression). Because the background elements are larger, they appear to be more out of focus, so the perceived DOF is smaller with a longer FL..

In practical terms, you need to experiment with different FLs on your camera to see what gives you the results you're after for isolating your subject from the background. You need to make a judgement about whether the perceived shallowing of DOF due to a longer FL seems to blur the background more than using a shorter FL, despite the longer FL not being able to use an f-stop as small as the shorter FL can use..

Cheers from John from Adelaide, South AustraliaJohn Harvey Photography http://johnharvey.com.auCanon 40D, Canon 20D & Fuji F10..

Comment #7

"Depth of field (DOF) is the range of sharp focus from near to far. Smaller DOF means the subject is isolated more and the foreground and background are blurred more, which is what you are after.".

Depth of Field and focus are very different beasts, camera obscura has lots of potential depth of field and no focus! Focus is from a point or plane in space to a point on the film plane (this is what the lens does). Depth of Field is created by the aperature not the focusing of the lens, circles of confusion, make up what is apparent sharpness in the out of focus areas of the image. The larger the circles of confusion ie f1.4 the softer the out of focus areas, the smaller the circles of confusion ie f22 the more apparent over all sharpness..

Point of clarification..

Comment #8

Kinnaird wrote:.

Depth of Field and focus are very different beasts, camera obscurahas lots of potential depth of field and no focus! Focus is from apoint or plane in space to a point on the film plane (this is whatthe lens does). Depth of Field is created by the aperature not thefocusing of the lens, circles of confusion, make up what is apparentsharpness in the out of focus areas of the image. The larger thecircles of confusion ie f1.4 the softer the out of focus areas, thesmaller the circles of confusion ie f22 the more apparent over allsharpness..

Point of clarification.

Do you even know how the CoC is defined (OK, there are many differing methods, but they all use the same process, just different standards for perceived acceptable sharpness)? If you did, you would know the f-stop has nothing to do with determining the CoC. The CoC is dependent on sensor size, not f-stop..

Also, DoF is most certainly determined by focus distance. Please read up on DoF before you give more inaccurate information..

The information from "John down under" was very accurate, other than he neglected to mention that in order for the DoF at a given f-stop being independent of focal length, the subject distance has to be much less than the hyperfocal distance...

Comment #9

Yanivecp wrote:.

Can I ask if I have control on the f-number for this camera , if sohow do I do that?.

In order to control the f-stop directly on the SD800 IS, you will need to use "Manual" mode (the one with the M on the dial, right under the full auto), since you do not have Av (aperture priority) mode on your camera. The simpler option is to use the "Portrait" mode (under the Scene modes) on your camera...

Comment #10

What I said is very accurate if you want to discuss some other topic fine. but don't pretend that it has anything to do with what I said!..

Comment #11

Kinnaird wrote:.

What I said is very accurate if you want to discuss some other topicfine. but don't pretend that it has anything to do with what I said!.

I believe you wrote the following:.

"The larger the circles of confusion ie f1.4 the softer the out of focus areas, the smaller the circles of confusion ie f22 the more apparent over all sharpness.".

This implies that the CoC is dependent on f-stop. That is just false. Most CoC formulas use an 8x10 print with a 10"-12" viewing distance to determine the amount of acceptable sharpness. This generally translates to a CoC of 0.025 to 0.035mm on a FF/35mm sized sensor..

See the following links:.

Http://dspace.dial.pipex.com/...puo76/digifotoinfo/articles/DOF/DOF%20how.htmhttp://www.dofmaster.com/digital_coc.htmlhttp://www.cambridgeincolour.com/tutorials/depth-of-field.htm.

P.S. Note that at the bottom of the second link, there is a calculator to determine the CoC. Note that the focal length questions are only to determine the sensor size. If you keep the ratio between real and effective focal lengths the same, you get the same CoC. Note that f-stop is not mentioned in this calculator...

Comment #12

Let's pretend this is a beginners forum, just for the sake of argument! My point is that the control you have over a given circle of confusion is aperature. I know full well how a lens creates them making control over them simple for a beginner to understand is the point I am coming from. What's your point?..

Comment #13

I'll get the marshmallows, can someone else bring the chocolate & graham crackers.I feel like S'Mores..

Comment #14

Kinnaird wrote:.

Let's pretend this is a beginners forum, just for the sake ofargument!.

OK..

My point is that the control you have over a given circleof confusion is aperature..

I didn't realize that aperture can control the CoC; I thought aperture controlled the DoF. I thought that sensor (or film format) size controlled the CoC..

I know full well how a lens creates themmaking control over them simple for a beginner to understand is thepoint I am coming from..

Well, "John down under" gave a very clear and well thought out explanation to the OP in terms that could be understood by a beginner. You decided to make a "point of clarification" to his post that did not clarify things, since the information that you gave was wrong. By the way, how does a lens create "circles of confusion?".

What's your point?.

To make a point of clarification..

P.S. I'll let you make the last post to this thread, since I will not post directly to you anymore on this thread. I've become tired of trying to discuss the technical aspects of DoF with you. I also do not like hi-jacking this thread to discuss something that the OP probably has no interest in...

Comment #15

Pointed:.

"In optics, particularly as relates to film and photography, the depth of field (DOF) is the distance in front of and beyond the subject that "appears to be in focus". "Although a lens can precisely focus at only one distance", the decrease in sharpness is gradual on either side of the focused distance, so that within the DOF, the unsharpness is imperceptible under normal viewing conditions".

"Depth of field (DOF) is the range of sharp focus from near to far.".

This not so subtle difference between these to statements is often misunderstood by beginners, personally I wouldn't want to be caught dead defending the second option! You have said the second statement is good sound advice, and it's your choice if you want to believe that, I won't be finger pointing and saying you are wrong but I will say that the difference between 'apparent focus' and 'sharp focus' is profound. Lots more can be said on this topic but this is not the right forum so I'll not discuss it here further...

Comment #16

Kinnaird wrote:.

"Depth of field (DOF) is the range of sharp focus from near to far.".

I would add just one word - acceptable - to the above:"Depth of field (DOF) is the range of acceptably sharp focus from near to far.".

The concept of what is "acceptable" is really the heart of any discussion of depth of field. For example a small print could appear acceptably sharp while an enlargement might appear unsharp.Regards,Peter..

Comment #17

Dave_s93 wrote:.

Kinnaird wrote:.

What I said is very accurate if you want to discuss some other topicfine. but don't pretend that it has anything to do with what I said!.

I believe you wrote the following:.

"The larger the circles of confusion ie f1.4 the softer the out offocus areas, the smaller the circles of confusion ie f22 the moreapparent over all sharpness.".

This implies that the CoC is dependent on f-stop. That is justfalse. Most CoC formulas use an 8x10 print with a 10"-12" viewingdistance to determine the amount of acceptable sharpness. Thisgenerally translates to a CoC of 0.025 to 0.035mm on a FF/35mm sizedsensor..

I don't see any problem or contradiction here..

The term "circle of confusion" is being used in two different contexts, which is fine..

One is the very specific size of the CoC used in depth of field calculations. This could be regarded as a fixed number..

The other is relating to the broad range of sizes in the out of focus areas. These will vary in size depending on the distance of the subject as well as the aperture..

Of these two usages, one does not imply the other, they each correctly deal with aspects of the concept of "circle of confusion".Regards,Peter..

Comment #18

Yanivecp wrote:.

Hi all.

I am using canon SD800 IS , I would like your help with this smallquestion:.

How do I take a picture that the main object is focused andeverything around him is blurry..

Is this a special shooting mode?.

Tx.

Wow, lots of talk and few straight answers..

Here's the short one: Your type of camera is generally not capable of taking images like that. Do it afterwards on your computer using something like Photoshop Elements...

Comment #19

My apologies for my part in straying from the spirit of your original post...

Comment #20

Kinnaird wrote:.

"Depth of field (DOF) is the range of sharp focus from near to far.Smaller DOF means the subject is isolated more and the foreground andbackground are blurred more, which is what you are after.".

Depth of Field and focus are very different beasts, camera obscurahas lots of potential depth of field and no focus! Focus is from apoint or plane in space to a point on the film plane (this is whatthe lens does). Depth of Field is created by the aperature not thefocusing of the lens, circles of confusion, make up what is apparentsharpness in the out of focus areas of the image. The larger thecircles of confusion ie f1.4 the softer the out of focus areas, thesmaller the circles of confusion ie f22 the more apparent over allsharpness..

Point of clarification.

Happy to change DOF to the range through which the scene is perceived to be in focus..

Cheers from John from Adelaide, South AustraliaJohn Harvey Photography http://johnharvey.com.auCanon 40D, Canon 20D & Fuji F10..

Comment #21

Dave_s93 wrote:.

Kinnaird wrote:.

Depth of Field and focus are very different beasts, camera obscurahas lots of potential depth of field and no focus! Focus is from apoint or plane in space to a point on the film plane (this is whatthe lens does). Depth of Field is created by the aperature not thefocusing of the lens, circles of confusion, make up what is apparentsharpness in the out of focus areas of the image. The larger thecircles of confusion ie f1.4 the softer the out of focus areas, thesmaller the circles of confusion ie f22 the more apparent over allsharpness..

Point of clarification.

Do you even know how the CoC is defined (OK, there are many differingmethods, but they all use the same process, just different standardsfor perceived acceptable sharpness)? If you did, you would know thef-stop has nothing to do with determining the CoC. The CoC isdependent on sensor size, not f-stop..

I thought CoC was dependent on the pixel density rather than sensor size..

Also, DoF is most certainly determined by focus distance. Pleaseread up on DoF before you give more inaccurate information..

The information from "John down under" was very accurate, other thanhe neglected to mention that in order for the DoF at a given f-stopbeing independent of focal length, the subject distance has to bemuch less than the hyperfocal distance..

Thanks. I didn't know that, so I'm glad I posted and you replied. What changes at or past the hyperfocal distance, and how does that change DOF?.

Cheers from John from Adelaide, South AustraliaJohn Harvey Photography http://johnharvey.com.auCanon 40D, Canon 20D & Fuji F10..

Comment #22

Greg Nut wrote:.

Yanivecp wrote:.

Hi all.

I am using canon SD800 IS , I would like your help with this smallquestion:.

How do I take a picture that the main object is focused andeverything around him is blurry..

Is this a special shooting mode?.

Tx.

Wow, lots of talk and few straight answers..

Here's the short one: Your type of camera is generally not capable oftaking images like that. Do it afterwards on your computer usingsomething like Photoshop Elements..

Greg, sure compact cameras are way more limited in achieving shallower DOF than are cameras with larger sensors, but some degree of separation is still possible between subject and foreground/background..

A better answer would include a suggestion to use the camera's smallest f-stop number, which might be achieved by using the portrait shooting program. It would also include the suggestion to have the subject much closer to the camera than the background..

Cheers from John from Adelaide, South AustraliaJohn Harvey Photography http://johnharvey.com.auCanon 40D, Canon 20D & Fuji F10..

Comment #23

John down under wrote:.

I thought CoC was dependent on the pixel density rather than sensorsize..

No, it is based on the sensor size. There are many conventions for determining the CoC. Most assume that the final print size is an 8x10 viewed at 10" or 12". The print size and viewing distance determines what is the smallest perceived dot on the *final* print. From this perceived dot on the final print, the CoC is then calculated with respect to the sensor/film format. There are many different conventions on determining what is the smallest perceived dot, however, most are in the range of .025mm to .035mm on a FF/35mm sensor..

See following links for more information:.

Http://dspace.dial.pipex.com/...puo76/digifotoinfo/articles/DOF/DOF%20how.htmhttp://www.dofmaster.com/digital_coc.htmlhttp://www.cambridgeincolour.com/tutorials/depth-of-field.htm.

Note that if you want to determine the DoF for a different print size and viewing combination, you will need to calculate the CoC. However, your viewing distance generally changes accordingly when you change your print size, so in practice, the CoC stays the same..

Thanks. I didn't know that, so I'm glad I posted and you replied.What changes at or past the hyperfocal distance, and how does thatchange DOF?.

When you are near the hyperfocal distance, you get more DoF on the wide angle lens. From the DOFmaster website, here is a graph of the DoF difference (note: this is for a FF/35mm sensor. The graph is similar for crop sensors, but the numbers would be different.).

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

See the following link for more information.http://www.dofmaster.com/dof_imagesize.html.

Hope this helps...

Comment #24

John down under wrote:.

Greg Nut wrote:.

Here's the short one: Your type of camera is generally not capable oftaking images like that. Do it afterwards on your computer usingsomething like Photoshop Elements..

Greg, sure compact cameras are way more limited in achievingshallower DOF than are cameras with larger sensors, but some degreeof separation is still possible between subject andforeground/background..

A better answer would include a suggestion to use the camera'ssmallest f-stop number, which might be achieved by using the portraitshooting program. It would also include the suggestion to have thesubject much closer to the camera than the background..

I did say "generally." not "absolutely." While what you suggest might work for a close-up of a flower, note that the OP referred to his subject as "him." From the distance people are usually photographed, getting an OOF background is quite unlikely using a p&s..

My point was simply that PP is the best way to achieve the desired effect with a p&s, not necessarily the only way..

BTW, the issue is actually the aperture of the lens, not the sensor. If it were possible to put a f/0.2 lens on a p&s, OOF backgrounds would be readily achieved...

Comment #25

Cheers from John from Adelaide, South AustraliaJohn Harvey Photography http://johnharvey.com.auCanon 40D, Canon 20D & Fuji F10..

Comment #26

I am using canon SD800 IS , I would like your help with this smallquestion:how do I take a picture that the main object is focused andeverything around him is blurry.is this a special shooting mode?.

Hopefully you found everything in this thread interesting..

The simple answer to your question is that it isn't a special mode and that unfortunately you can't really do it with your camera, though you can a bit, if you know what to do:.

1. Zoom in2. Get close to your subject (macro mode works best if appropriate)3. Keep the background far away.

4. Shoot in dimmer conditions to make the camera use a bigger aperture but don't use flash.

Even so, you'll only get the effect to a certain extent, and not only that, but the blur you get won't be as nice as if you'd used an SLR..

Androohttp://Androo.smugmug.com..

Comment #27

Greg Nut wrote:.

John down under wrote:.

Greg Nut wrote:.

Here's the short one: Your type of camera is generally not capable oftaking images like that. Do it afterwards on your computer usingsomething like Photoshop Elements..

Greg, sure compact cameras are way more limited in achievingshallower DOF than are cameras with larger sensors, but some degreeof separation is still possible between subject andforeground/background..

A better answer would include a suggestion to use the camera'ssmallest f-stop number, which might be achieved by using the portraitshooting program. It would also include the suggestion to have thesubject much closer to the camera than the background..

I did say "generally." not "absolutely." While what you suggestmight work for a close-up of a flower, note that the OP referred tohis subject as "him." From the distance people are usuallyphotographed, getting an OOF background is quite unlikely using a p&s..

My point was simply that PP is the best way to achieve the desiredeffect with a p&s, not necessarily the only way..

Hi Greg. OK. It just sounded to me like you were telling the OP to give up if he wasn't prepared to Photoshop, and I'm not a big fan of the results from Photoshop unless the image lends itself to that treatment and it's done skillfully..

BTW, the issue is actually the aperture of the lens, not the sensor..

Yes. That's what I was saying in my long reply above.http://forums.dpreview.com/...forums/read.asp?forum=1002&message=27021105.

If it were possible to put a f/0.2 lens on a p&s, OOF backgroundswould be readily achieved..

As you say, tough to get a large aperture (entrance pupil) on a compact camera (with it's short lens)..

Cheers from John from Adelaide, South AustraliaJohn Harvey Photography http://johnharvey.com.auCanon 40D, Canon 20D & Fuji F10..

Comment #28

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