Hmmm.... Long story (the optical/scientific side) - I won't go into that. Still, the DOF remains unchanged. DOF is a function of Aperture and Focal length an focusing distance - nothing else. However, since you normally use shorter focal lengths for a smaller (digital) format (to get the sam AOV), the DOF seemingly gets better (deeper) for the smaller (digital) format, provided the AOV is the same.
I too noticed, that a little while ago, there was a posting (Paul Stenquist??) saying something about the DOF on a digital camera being different from that of the same lens, used on a 35mm body...??? I believe what he meant was, that a 300mm on the *ist D will equal a 450mm in terms of magnification on a 35mm, but still have the DOF of a 300mm, which - I believe - is true. So, I believe what you are saying about the 50mm and the 85mm may very well be correct. But of cource, by cropping the image (by using a smaller format) you may in some cases also cut away some of the "out of focus" areas, which may appear as better DOF. Jens Bladt mailto:[EMAIL PROTECTED] http://hjem.get2net.dk/bladt -----Oprindelig meddelelse----- Fra: Albano Garcia [mailto:[EMAIL PROTECTED] Sendt: 2. januar 2005 20:56 Til: PDML Emne: Sensor-Size-Conversion-Factor-Confused... HELP Hi gang, I understand the APS sized sensors on DSLRs converts your 28mm on a 42mm cropping image area, but if I understand well, the depth of field remains the one of a 28mm and also the distortion of image proper of the original focal lenght remains, since the lens is still phisycally the same, but cropped, right? So, people who uses 50mm lenses as short teles for portraits, still gets the dof and face features rendition of a 50mmm but cropped, not the flatting effect of a 85mm... I'm right? Regards ===== Albano Garcia Photography & Graphic Design http://www.albanogarcia.com.ar http://www.flaneur.com.ar __________________________________ Do you Yahoo!? Read only the mail you want - Yahoo! Mail SpamGuard. http://promotions.yahoo.com/new_mail
