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Old Apr 22, 2004, 10:59 AM   #1
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Default DOF question? effect of different lenses and cameras

Ok I this a three par t question I have been curious about.
Do differnt cameras produce differnet dof with the same lense?
Do different lenses at the focal length produce differnt dof?
Do 33mm cameras have different dof at the same focal length and same aperture then dslr?
What causes the differnet different DOF?

I saw a little information about this subject in the photo of the week contest forum but thought I would ask for more info.
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Old Apr 22, 2004, 5:16 PM   #2
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People should feel free to correct me!

1) No, I do not believe so.
2) Yes, if the physical size/diameter of the lens is different. A digicam (with a very small lens to match its very small sensor) will have much larger DOF than my 10D at the same focal length. But that is probably not what you were asking. My 100-400L at 100mm will have the same DOF as my 28-135 @ 100mm.
3) No.

DOF is controlled by several factors.
aperture size.
distance to subject.
focal length.

Check out this link for more info:
http://www.dpreview.com/learn/?/Glos...f_field_01.htm

Eric
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Old Apr 22, 2004, 5:46 PM   #3
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I knew the digital cameras with the smaller ccd have much greater dof at the same focal length. I didn't know why it had to do with the sensor size but now I understand. I wasn't sure if dlsr's using only the center of the lense would have different dof with same lense at the same focal length. Thanks for all the info it makes sense to me.
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Old Apr 22, 2004, 10:44 PM   #4
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Just to be clear, it isn't that the sensor is small, it's that they build a small lens to match it.

At least, that is how I understand it.

Eric
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Old Apr 22, 2004, 11:22 PM   #5
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Default Re: DOF question? effect of different lenses and cameras

Quote:
Originally Posted by iblaineman
What causes the differnet different DOF
It's the physical size of the aperture relative to the size of the big wide world outside the camera. A pinhole camera has a tiny aperture and an enormous depth of field.

A tiny pocket digicam (or a camcorder) has a very short focal length lens, so when you expose at, say, 1/500s at f/4, this is a very small hole, more like a pinhole camera than if you have a large lens on a dSLR or a 35mm SLR, or even more so than if you have a huge antique 10x8 plate camera.
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Old Apr 23, 2004, 9:05 AM   #6
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The only thing I'd add is that you have to compare the focal lengths and not include any multipliers.

That is, a 100mm lens on a 300D has the same DOF as a 100mm lens on a film SLR. The resulting photos will look different because the 300D crops the image giving it the look of a 160mm lens but with a 100mm lens' DOF.
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