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DOF question
Hi,.

Is there any way to find easily the Depth Of the Field (until what distance from camera, objects are sharp), with a digicam (Canon powershot s80) given a focal/aperture value (f/) ? .

In the film cameras there were some indications on top of the lens. But how about a digicam with no indication?.

What I am looking for is an easy way, without calculation (no time to find before shooting!), something like a rule of thumb..

Also i'd like to know, once the aperture for a given distance sharpness is set, where the focus is done:A/ with automatic focusB/ with manual focus: in this case to what distance should I focus ? .

My objective is to go to the manual program with manual focus and take pictures very quickly. Of course these will be same-style-pictures e.g. kids at 2 to 4 meters ( I could have different pre-settings for different situations/picture styles on custom mode). The point is to very quick shooting without time spent for camera to calculate exposures and focus. Please tell me if i'm all wrong and there is a better way to do this..

Many thanksanouch..

Comments (9)

Anouch wrote:.

Hi,.

Is there any way to find easily the Depth Of the Field (until whatdistance from camera, objects are sharp), with a digicam (Canonpowershot s80) given a focal/aperture value (f/) ? .

No, not that I'm aware of. It's too complex. If you donm't have Barnack, get it:.

Http://www.stegmann.dk/mikkel/barnack/.

It will do these computations for you. It doesn't have the S80 in the database, but you can use the A620 and get correct answers. Or send Mikkel an e-mail and he will add the S80 to the database..

In the film cameras there were some indications on top of the lens.But how about a digicam with no indication?.

This is one thing that I wish camera manufacturers would include in cameras. It's easy for the little uP in a camera to compute the DOF and tell us!.

What I am looking for is an easy way, without calculation (no time tofind before shooting!), something like a rule of thumb..

With the S80, there is a very wide DOF..

Also i'd like to know, once the aperture for a given distancesharpness is set, where the focus is done:.

I don't quite understand that sentence?.

A/ with automatic focus.

In small "digicams", the camera uses data from the sensor to make the contrast as high as possible in the selected focus area. This is essentially the way humans focus..

B/ with manual focus: in this case to what distance should I focus ? .

I'm not familiar with the S80 and how it's MF mode works..

My objective is to go to the manual program with manual focus andtake pictures very quickly. Of course these will besame-style-pictures e.g. kids at 2 to 4 meters ( I could havedifferent pre-settings for different situations/picture styles oncustom mode). The point is to very quick shooting without time spentfor camera to calculate exposures and focus. Please tell me if i'mall wrong and there is a better way to do this..

Fully manual mode is indeed quick. In general, your camera doesn't take long to "meter the exposure". I'd suggest that, if possible, you let the camera expose but lock the focus to an average distance. You might Google "hyperfocal distance" and read? There is a good section in Wikipedia on this!.

Charlie DavisNikon 5700 & Sony R1HomePage: http://www.1derful.infoBridge Blog: http://www.here-ugo.com/BridgeBlog/..

Comment #1

Chuxter wrote:.

No, not that I'm aware of. It's too complex. If you donm't haveBarnack, get it:.

Http://www.stegmann.dk/mikkel/barnack/.

Thanks for that!..

Comment #2

First of all thanks very much for your explanationI'll check your web pages.

Chuxter wrote:.

It will do these computations for you. It doesn't have the S80 in thedatabase, but you can use the A620 and get correct answers. Or sendMikkel an e-mail and he will add the S80 to the database..

That's ok for theory but i'm not gonna do this for each shooting!.

I need to do it on feeling. For example how do you do it ? how are your sure for object sharpness for a given aperture ? I need to know how general users do it..

With the S80, there is a very wide DOF..

Why is that? Is it because of the lens focal ? how you deduce your stateement ? .

I don't quite understand that sentence?...I'm not familiar with the S80 and how it's MF mode works..

My question is simply to know that if I enable manual focus, then to what distance should I focus for the entire DOF be sharp. I think I should focus in the middle of the DOF or something ? .

Fully manual mode is indeed quick. In general, your camera doesn'ttake long to "meter the exposure". I'd suggest that, if possible, youlet the camera expose but lock the focus to an average distance..

Actually I have set the custom mode to aperture priority mode (auto speed):f5.6, flash and manual focus..

In this way I shoot indoor at night with little light (autofocus takes long and sometimes impossible) and within 2 to 4 meters..

I want to find another kind of preset for outdoor without flash and a max of DOF. What setting would you use ? .

Thanks a lotanouch..

Comment #3

You could make yourself a small chart and print it on a 3 x 5 card. Just use an online calculator for the settings..

Http://www.dofmaster.com/dofjs.html.

Brian A...

Comment #4

Anouch wrote:.

First of all thanks very much for your explanationI'll check your web pages.

Chuxter wrote:.

It will do these computations for you. It doesn't have the S80 in thedatabase, but you can use the A620 and get correct answers. Or sendMikkel an e-mail and he will add the S80 to the database..

That's ok for theory but i'm not gonna do this for each shooting!I need to do it on feeling. For example how do you do it ? how areyour sure for object sharpness for a given aperture ? I need to knowhow general users do it..

Gerenal users don't. They just point & shoot. Thinking is for geeks and nerds... .

With the S80, there is a very wide DOF..

Why is that? Is it because of the lens focal ? how you deduce yourstateement ? .

Well, I've been doing photography for 40 years. Picked up a few facts along the way. A degree in Physics helped a bit..

You can use Barnack to figure these things out. That's why I gave you the link. It will let you do "what if" kinda things...like make the sensor smaller and the FL shorter and see what happens to the DOF....

I don't quite understand that sentence?...I'm not familiar with the S80 and how it's MF mode works..

My question is simply to know that if I enable manual focus, then towhat distance should I focus for the entire DOF be sharp. I think ishould focus in the middle of the DOF or something ? .

Read about hyperfocal distance. That will answer your question..

Fully manual mode is indeed quick. In general, your camera doesn'ttake long to "meter the exposure". I'd suggest that, if possible, youlet the camera expose but lock the focus to an average distance..

Actually I have set the custom mode to aperture priority mode (autospeed):f5.6, flash and manual focus.In this way I shoot indoor at night with little light (autofocustakes long and sometimes impossible) and within 2 to 4 meters..

I want to find another kind of preset for outdoor without flash and amax of DOF. What setting would you use ? .

To get max DOF, you need to:.

1. Make the sensor small2. Make the FL short3. Make the aperture small4. Make the subject far away.

Or some combination of these. To change the sensor size, you would have to buy a different camera with a 1/2.5" or 1/2.7" sensor. This would have terrible IQ, but you didn't say you wanted a good picture, just wanted max DOF. .

Once again, playing around with Barnack will tell you all these answers!.

Charlie DavisNikon 5700 & Sony R1HomePage: http://www.1derful.infoBridge Blog: http://www.here-ugo.com/BridgeBlog/..

Comment #5

Unfortunately you cannot get the CHDK that gives you that. Presently only A610, A620, A630, A640, S2, S3 and G7 are supported.VictorBucuresti, Romaniahttp://s106.photobucket.com/albums/m268/victor_petcu/..

Comment #6

Recently tried useing DOF master w 5D & 100m and subjects in the 3 to 6 foot range...found it to be wrong....I was only getting about 1/2 to 1/3 the DOF it was telling me I should get....?..

Comment #7

Steven Major wrote:.

Recently tried useing DOF master w 5D & 100m and subjects in the 3 to6 foot range...found it to be wrong....I was only getting about 1/2to 1/3 the DOF it was telling me I should get....?.

The whole DoF thing is very subjective. There is a plane of focus, everything else is OoF to varying degrees. It comes down to what is "acceptably" in focus to you..

With a pin hole camera, for example, everything to infinity is "in focus", but nothing is sharply in focus..

Brian A...

Comment #8

Try Barnack. It's complex and allows you to vary the circle of confusion (COC)..

BTW, COC is NOT a bunch of BQF members trying to confuse each other... .

Charlie DavisNikon 5700 & Sony R1HomePage: http://www.1derful.infoBridge Blog: http://www.here-ugo.com/BridgeBlog/..

Comment #9

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