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05-26-2007, 07:38 PM   #1
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Questions on Lenses

Was wondering if stops on different lenses were the same size. Like is f/11 the same size on all lenses? Or is it perportional to the specific lens.

Also wondering if the same stop is the same depth of field. Like if f/11 was the same DOF on all lenses.

No real reason to know. Just been wondering.

05-26-2007, 08:58 PM   #2
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The physical size of apertures will vary based on design, materials, and, as you suspected, proportions of the lens. The dimensions of the depth of field will vary as well.

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05-26-2007, 10:09 PM   #3
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QuoteOriginally posted by Brainless Quote
Was wondering if stops on different lenses were the same size. Like is f/11 the same size on all lenses? Or is it perportional to the specific lens.

Also wondering if the same stop is the same depth of field. Like if f/11 was the same DOF on all lenses.

No real reason to know. Just been wondering.
As for the exposure, all lenses will let in the same amount of light given the same aperture, e.g. f/11.

As for DOF, it varies with the aperture and focal length. If two lenses have the same focal length and f/stop, they will have the same DOF.
05-27-2007, 06:00 AM   #4
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QuoteOriginally posted by Brainless Quote
Was wondering if stops on different lenses were the same size. Like is f/11 the same size on all lenses? Or is it perportional to the specific lens.

Also wondering if the same stop is the same depth of field. Like if f/11 was the same DOF on all lenses.

No real reason to know. Just been wondering.

f/11 is not the same size on all lenses. It is the same size on all lenses of the same focal length. The size of the aperture opening is based on the focal length and f stop number: "Area=3.14 x (f/2N)squared" f is focal length, N is f-stop.

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