Archived posting to the Leica Users Group, 2004/02/19
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]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. 2) Actually the smaller chips are not the resolution champs as those 5 mp tiny chips do not produce anywhere near the quality of a 5 mp large chip. Tiny chips result in high S/N levels, interference and deterioration due to the high magnifications required. While some pros have been tossing their medium format gear after buying digital, it is large sensor cameras that have them doing this, not digital Elfs. So the reason small chips have greater DOF is the fact that they are low resolution devices. Low resolution makes it harder to discern differences between the sharp areas and the not quite as sharp areas. Thus giving greater DOF or, in plain-speak, a wider band of crap. John Collier On Feb 18, 2004, at 7:28 AM, Robert Rose wrote: > Maybe this was covered by others (I can't keep up with all the posts). > > Here is my understanding of why digital has greater DOF: > > There are two reasons: > 1) You are shooting with a (for example) 50mm lens cropped to a 75mm > field of view. Therefore, you are getting the deeper DOF of the wider > 50mm lens with the apparent field of view of a longer 75mm lens. The > effect is that of a 75mm lens with a deeper field of view. It is > identical, however, to shooting & cropping on film. > > 2) The circle of confusion in digital is smaller than in film. This > means that even with a full frame sensor, digital should have deeper > apparent field of view. In this regard, currently the cheaper P&S > cameras have the smallest pixel sizes (around 3 microns) and therefor > are the resolution champs, and should have the smaller circle of > confusion (assuming the lens is up to the job). > > > Bob Rose > -- > 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