Neil... In my opinion, there is NO magnification factor.... using a sensor ( film or otherwise) only changes the field of view or angle of view of the sensor. Relative comparisons can be easily studied by relative ratios, and using a term like magnification factor is fine in that context. Frank Filippone red735i@xxxxxxxxxxxxx I agree with your analysis, except for the "apparent FL" aspect. The field of view changes as you've described, but the magnification factor does not. Best regards, Neil ------ Unsubscribe or change to/from Digest Mode at: http://www.lrflex.furnfeather.net/ Archives are at: //www.freelists.org/archives/leicareflex/