Archived posting to the Leica Users Group, 2004/02/19
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]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 - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html