On 28 Nov 2002 at 12:12, Herb Chong wrote: > Message text written by INTERNET:[EMAIL PROTECTED] > >From 36*24mm, you need to enlarge roughly 5 times to get a 5*7. > From 24*16mm - surely you need to enlarge by 7 times to get the same > 5*7? > > What has this to do with pixels?< > > there is an additional factor, pixel count. think if you had 1 pixel per > millimeter. it doesn't affect what gets focused on the sensor, but it does > affect what you are able to see when you enlarge.
Apart from the fact that DOF has everything to do with final print viewing distance. The limits of DOF are defined as the point at which the the image becomes visibly unsharp and the equation assumes that as prints are reproduced larger they should be viewed at an increased distance so as to maintain the apparent size. Conventional DOF calculations CAN NOT be directly applied to digital systems in all cases, consider the implications of using a 640 x 480 matrix to capture full frame 35mm images? Also consider that in all sensor except Foveon a single pixel in the print is formed by the computing its value form at least 4 other single colour pixels. Anyone want to take a stab at the math? Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications.html
