Archived posting to the Leica Users Group, 1999/08/19
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Douglas Williams <dwilli19@ford.com> wrote: > > Last night, for the first time (I don't know why I didn't try before) > I mounted my later model 50mm Summicron-M on my M3. As I was adjusting > the focus on something about 1.2m (3 feet or so), the rangefinder image > stopped adjusting. Looking at the body without the lens attached, I see > that the focussing arm/cam (that follows the lens to focus the > rangefinder) only has a limited amount of range, and thus would not come > out (forward) far enough to follow the lens cam. Apparently the arm > will not follow the lens cam through the entire range. Is this correct > on the M3? Is there something wrong with either the lens or the M3 > which would prevent me from focussing down closer than 3 feet? The M3 > was recently CLA by Sherry, so I am thinking it is an issue of > compatibility? The 50mm lenses contemporaneous with the M3 (notably the 50mm Collapsible Summicron and the 50mm Rigid Chrome Summicron) had minimum focusing distances of one meter (40 inches). The M3 is not as fully compatible with the current 50mm Summicron as later bodies like the M6 are. > My DR Summicron (on the M3) seems to focus down to the 18 inches with > the eyes, like it should! Perhaps the lens is at fault? Look again: the DR Summicron also has a minimum focusing distance of one meter when normally-focusing. When switched to the near-focusing, a second cam engages the rangefinder; mechanically the rangefinder then moves through the exactly the same range as in the normal-focusing regime. The DR eyes provide the optical transformation to shift the rangefinder patch and adjust the viewfinder magnification to permit near focusing. But mechanically, the rangefinder has not changed. Everything is working as designed, though perhaps not as you would like! - -- Pieter Bras