Archived posting to the Leica Users Group, 2004/02/19
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]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. - -----Original Message----- From: owner-leica-users@mejac.palo-alto.ca.us [mailto:owner-leica-users@mejac.palo-alto.ca.us] On Behalf Of Jacques Bilinski & Barbara Bradbury Sent: Thursday, February 19, 2004 5:40 PM To: leica-users@mejac.palo-alto.ca.us Subject: Re: [Leica] Digital DOF > 1) Sorry, not right. Increasing magnification, and keeping the other > variables the same: shooting distance, aperture and output -- say 4x6 > print at 18 inches, you are reducing apparent DOF. > I'm still having trouble with this. I thought that a major complaint of the small sensor digital cameras was that you cannot shoot portraits with the background out of focus like you can with 35mm. So if you take 2 pictures - one with a small sensor digital and one with a 35mm from the same location (same perspective, different focal lengths, same f stop), and then print both on a say 4x6 print. Will not the 35mm shot show a more out of focus background? - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html