ka_ho_wong Posted September 14, 2004 Share Posted September 14, 2004 Anyone has done that before? Link to comment Share on other sites More sharing options...
jorge Posted September 14, 2004 Share Posted September 14, 2004 No, not as far as I know. It's not possible within practical terms. The reason is that the M mount is 1mm closer to the film than the screw mount. This allows for an adapter for screw lenses to fit M cameras but not the other way around. Link to comment Share on other sites More sharing options...
huw_finney Posted September 14, 2004 Share Posted September 14, 2004 I would say yes, my IIIb mount is 1.5mm thick (ish) so an M mount would still be in front of the front(!), might need a bit of machining of the body. Link to comment Share on other sites More sharing options...
jeroen dommisse Posted September 14, 2004 Share Posted September 14, 2004 <i>I would say yes</i> <p> Well, it does sound like another mad project, doesn't it? Link to comment Share on other sites More sharing options...
jorge Posted September 14, 2004 Share Posted September 14, 2004 Well, probably a good machinist would tackle it. Still, there's the matter of the latch. Link to comment Share on other sites More sharing options...
dan flanders Posted September 14, 2004 Share Posted September 14, 2004 I've miked it and think it is possible but wheter it is feasible is a different can of worms. The other way around seems more feasible. Some M lenses seem a possibility. The 135/4.0 Elmar has a mounting flange thick enough that two mm could be turned off and a one mm screw mount flange mounted thereto. The 90/4.0 Elmar C has a flange that is thick enough and is fastened to the barrel with screws which would allow its removal and replacement with a screw mount flange of the proper thickness. Obviously it all depends upon whether the mounting flange is thick enough to permit the removal of two mm and fitting a one mm screw mount. In any event it would be an expensive proposition unless you have a machine lather and know how to use it. Link to comment Share on other sites More sharing options...
ben z Posted September 14, 2004 Share Posted September 14, 2004 I think I remember reading somewhere that Leica made some IIIg's with M mount as prototypes. Also I remember speaking with Reinhold Mueller, the Leica repairman in Toronto, a number of years ago and he said he was working on such a modification. Link to comment Share on other sites More sharing options...
huw_finney Posted September 14, 2004 Share Posted September 14, 2004 Harry, The 135/4 also has a removable mount, I bet they where spares once! Link to comment Share on other sites More sharing options...
jorge Posted September 15, 2004 Share Posted September 15, 2004 I would love adapting a Summicron 50 -any version- to LTM but ignore if it's possible. I have a frined who's an able machinist but dunno if his up to the task. Link to comment Share on other sites More sharing options...
mark_sampson Posted September 15, 2004 Share Posted September 15, 2004 Jorge, the collapsible 50mm Summicron was made in screw mount- in fairly large numbers, IIRC. Link to comment Share on other sites More sharing options...
dan flanders Posted September 15, 2004 Share Posted September 15, 2004 HUW: If you mean the removable head I am quite aware of it and have ascertained that the focusing unit is proper for the head. In this instance I am concerned with the flange at the rear carrying the bayonet mount. On my lens it is a bit over three mm thick which would permit it't reduction in a lathe to one+/-mm that would accept the one mm thick screw mount flange. Frankly, I might attempt it in the case of the Elmar C (the flange on the C is fastened with three screws making it detachable), but only from curiosity -- I've a surfeit of useable Barnack and M gear to last the rest of my days in this veil of tears. Link to comment Share on other sites More sharing options...
jcgoodman Posted September 16, 2004 Share Posted September 16, 2004 Another thing to consider - The screw-mount flange on leicas up to, and including, IIIb are attached to the camera body. From IIIc onwards, including M's, the mount is attached directly to the camera internal chassis, creating a more rigidly-preserved lens-to-film distance. This is why, on the later cameras, the top-plate, chassis and lens-mount all come out in one piece when camera is dismantled.Any machining on a IIIa around the lens-mount opening, as well as all the other work involved, might create extra work/worry for the mechanic in resetting everything to hold, or improve upon, the original lens/film tolerance ( + or - 0.02mm if I remember rightly). Link to comment Share on other sites More sharing options...
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