How do you decide on DOF???


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Oly5050

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Feb 1, 2005
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#1
OK, another question.....how do you decide what f number to use if you are shooting in Aperture mode? Obviously I know that if I want bokeh +++, I dial it to the lowest f number. But how do you choose your numbers in between? Is there some kind of guide with regard to f and DOF? Am I correct to think that you get a certain DOF in terms of cm, with regard to certain f? Is there such a thing and is this kind of correlation correct on the ground? Thanks!
 

microcosm

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Sep 17, 2006
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#2
This is where you will need a DOF calculator. There is actually one...

So you decide how much bokeh or how much DOF do you need in your picture...

Happy calculating and shooting. Using DOF to your advantage is what makes a good pic from a bad one.
 

Oly5050

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Feb 1, 2005
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OK...thanks! Sounds like more complicated that I expected. In any case, I got no Palm so cannot calculate or d/l the program. Is there some rule of thumb that you all use that you have developed through experience? I am sure you dun calculate it everytime u take a shot right?
 

microcosm

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Sep 17, 2006
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OK...thanks! Sounds like more complicated that I expected. In any case, I got no Palm so cannot calculate or d/l the program. Is there some rule of thumb that you all use that you have developed through experience? I am sure you dun calculate it everytime u take a shot right?
Pick up a book to understand the intricate workings of using DOF... this has got to do with the distance the shooter is from the subject... you should spend time to read up and experiment and understand your gear to totally learn to master using DOF to compose your image, and it is only then your image will work very well in depth. Too much to talk in a forum thread.
 

holidaydom

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Aug 18, 2006
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make use of DOF preview button, if you camera has it.
You can enable this function on the camera.

Basically when you activate this function, the lens stops down and yuo will notice:
1) The image in the viewfinder becomes slightly darker
2) You'll be able to see the DOF for that aperature setting (zone of sharpness)
 

microcosm

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Sep 17, 2006
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make use of DOF preview button, if you camera has it.
Yes, you can use the preview button on your camera, but on consumer cameras where the viewfinder is not huge, and dim (esp with E-330), it is hard to see the effects of DOF.
 

holidaydom

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Aug 18, 2006
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Every lens has different DOF characteristics due to the focal length and aperature abilities (max aperature, number of aperature blades)

A good way to get to know your lens is to shoot a row of books on a shelf from an oblique angle.

> Setup a tripod and focus on the spine of a particular book...

> Start shooting at the lowest F stop and work your way up to F22 or whatever is the max.

> Then shift your position closer or further but still mantaining the same angle and still focusing on the same book and repete the process.

You should find that:
1) DOF increases with increasing F(number) (@ same focal length and same subject distance)
2) DOF decreases with increasing focal length (wide angle lenses have more DOF than tele lenses) (@ same aperature and same subject distance)
3) DOF increases when the distance between you and your subject increases (@ same focal length and same aperature)

Or you can google aperature to readup and learn more.

But nothing beats seeing for yourself if you ask me... ;)
 

cjtune

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Mar 20, 2006
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You should find that:
1) DOF increases with increasing F(number) (@ same focal length and same subject distance)
2) DOF decreases with increasing focal length (wide angle lenses have more DOF than tele lenses) (@ same aperature and same subject distance)
3) DOF increases when the distance between you and your subject increases (@ same focal length and same aperature)

Or you can google aperature to readup and learn more.

But nothing beats seeing for yourself if you ask me... ;)
Also, knowing the concept of hyperfocal distance is useful, esp. for landscapes.
 

holidaydom

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Aug 18, 2006
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#10
Also, knowing the concept of hyperfocal distance is useful, esp. for landscapes.
Care to share more on that?

I've readup on that but don't fully comprehend...

If I'm shoting a landscape, will it be better to focus to infinity and set to f11/f16 (let the camera figure out the best shutter speed)?

What's the correct way to determine the hyperfocal distance?
 

drakon09

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Aug 12, 2005
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#11
Moving this to the General section as this is about general photography and not specific to FourThirds.
 

ykia

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Apr 23, 2005
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#12
It's a compromise of background details, subject isolation & shutter-speed required for the subject...

Macros are between F/5.6 ~ F/13 with 100mm lens

Landscapes are F/11 and above with a 16-35mm lens

Portraits are F/2 ~ F/5.6 with 50mm lens

A lot depends on your subject and your taste.
 

cjtune

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Mar 20, 2006
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#13
Care to share more on that?

I've readup on that but don't fully comprehend...

If I'm shoting a landscape, will it be better to focus to infinity and set to f11/f16 (let the camera figure out the best shutter speed)?

What's the correct way to determine the hyperfocal distance?
For any given aperture size and focal length, there could be a minimum focusing distance whereby your DOF starts from there and stretches to infinity. Basically it's focusing to infinity, and that point you start to achieve that is called the hyperfocal distance.

You can use online DOF calculators or your lens' DOF charts to determine the hyperfocal distances.
 

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