Archived posting to the Leica Users Group, 1998/01/29
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Marc Small wrote: >Well, for starters, they have different lengths and thus MUST be a different formula. Harold Merklinger, a Canadian optical scientist, has written on this -- see his web page for details: http://fox.nstn.ca/~hmmerk/HMbook15.html For another, the COLLECTORS CHECKLIST TO LEICA CAMERAS lists a different UK patent number for the rigid from the collapsible. My copy is not at hand, nor have I ever compared the two. Marc< I have both lenses for my M3. These are in roughly the same condition. The rigid one I have was made in 1957 and the collapsible was made in 1955. I was curious about any performance difference and a few years ago I tested them on an optical target. At f 2.0 and f 5.6 (the two apertures I tested) the performance was nearly the same. The rigid seemed marginally better at the edges at 5.6, but this could just be a normal variation in the testing. So I guess the important point is that I'd feel comfortable using either lens. Charlie