New M-A, lens seating problem

[250swb]

Advertisement (gone after registration)

1 hour ago, TomB_tx said:

Depending on the lens body design, strong tension on the mounting lugs can slightly distort the nearby lens body, and if the focus helicoid is in that area it can slightly bind the focus. I have a 1955 M3 that is very tight to mount lenses, and a few lenses definitely increase focus effort on that body - but not on other bodies.

No too many years ago Leica recalled a new lens (maybe 21 Super Elmar?) and beefed up the body near the mount because of this issue. Some users never noticed a problem, as the mount tightness varies body to body.

Well that's a new one on me. A common cause of stiff focusing is that over the years the torque of mounting the lens causes the flange to twist back and forth and the screws loosen slightly causing the flange to go off-centre. It's just a case of loosening all the screws and retightening them gradually. I'd certainly try that before bending the springs in the lens mount.