Archived posting to the Leica Users Group, 2004/02/19
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At 9:51 PM -0500 2/19/04, Don Dory wrote:
>Jacques:
>It is not the sensor size that is determining the DOF. It is the lens
>focal length. On a small P&S digital you might have a 5-16mm focal
>length zoom roughly equivalent in image magnification to a 35-105 in
>35mm. So if you were doing a portrait using the 16mm focal length on
>the P&S and a 100mm on the 35mm from the same position and aperture then
>you would indeed have very different DOF on any reasonable image size.
>Now, if I used a 16mm lens on my 35mm and cropped to the same image size
>then the DOF would be the same assuming the same aperture, distance to
>subject, and image size on finished image.
>
>Some of the confusion is coming from magnification factors with digital
>SLR's using different focal length lenses to put the same image on the
>ground glass. Using the E-1 as an example, a 50mm lens magnifies like a
>100mm on a full frame digital or normal 35mm. The 50mm retains the same
>DOF properties that it would have on 35mm so the DOF using the Olympus
>system at a given aperture and image magnification would be greater than
>the DOF that would happen with a 35mm system, 100mm lens, same aperture,
>and same image magnification.
>
>I hope that this helps.
I doubt it will. Sensor size, or rather the relationship between
sensor size and the final image is indeed important in determining
DOF.
Once again you are ignoring CoC considerations; ie, DOF on the
negative is not the same as DOF on the print.
- --
* Henning J. Wulff
/|\ Wulff Photography & Design
/###\ mailto:henningw@archiphoto.com
|[ ]| http://www.archiphoto.com
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