I have a doggie M2 and a Wetzlar 50/2 Summicron Black. The range finder of on the M2 seems acurate despite the rewind knob having been knocked into the top case hard enough to cause a outward's bulge under the Leica logo. I have tested it with a friend's 50/1.4 (newest model) and infinity focus is right on. Vertical alignment is also good. With my Summicron at infinity the rangefinder misaligns by about a half mm. It is obviously the lens cam, as you can see and feel the wear on it. Is it possible (and cost effective) to have this replaced?