shaozhuohong Posted March 10, 2009 Share #1 Posted March 10, 2009 Advertisement (gone after registration) Can I ask the function of "Infinity Lock" in Leica Lens? I feel its very unconvenient with this lock............ Link to post Share on other sites More sharing options...
Advertisement Posted March 10, 2009 Posted March 10, 2009 Hi shaozhuohong, Take a look here About the "InfinityLock" in Leica Lens. I'm sure you'll find what you were looking for!
earleygallery Posted March 10, 2009 Share #2 Posted March 10, 2009 This has been debated here before, no one knows the answer but the majority opinion was that it is to aid the changing of lenses (so the barrel is locked to enable you to turn it easily). This doesn't explain why the early fixed lens Leicas also had infinity locks however Another Leica mystery. Link to post Share on other sites More sharing options...
Philippe D. Posted March 10, 2009 Share #3 Posted March 10, 2009 I don't know if the question is a kind of argument to post a picture of the lens, but this is a very nice and exceptional rare lens you are showing us here. Link to post Share on other sites More sharing options...
Michael Hiles Posted March 10, 2009 Share #4 Posted March 10, 2009 I don't know if the question is a kind of argument to post a picture of the lens, but this is a very nice and exceptional rare lens you are showing us here. Looks like a rigid Summitar - I didn't know such a lens existed. It also looks like an M mount, but hard to be certain...??? Anyone know any more? Link to post Share on other sites More sharing options...
luigi bertolotti Posted March 10, 2009 Share #5 Posted March 10, 2009 Hmmm... "Betriebsk" i.e. "internal use" lens... Summitar * ("star") i.e. prototype of Summicron... number seems "normal" i.e. not of the 0000xxx kind and looks in the range of 9xx.xxx, correct for the timeframe: VERY interesting item !!! Post other pics of it !!! Link to post Share on other sites More sharing options...
lars_bergquist Posted March 11, 2009 Share #6 Posted March 11, 2009 Nearly all early Leica lenses, fixed or interchangeable, had single focussing helicals. This means that as you focussed the lens, the optical cell, i.e. the entire front part of the lens, rotated. Consequently, changing the aperture was difficult as it just made the lens rotate in its helical. But as long as the lens was ar infinity it was locked and fiddling with the fiddly aperture tab on e.g. a 5cm Elmar was much easier. So you set the aperture first, and focussed later, which is still the proper sequence! Nine and thirteen-point-five centimeter lenses had modern-style aperture rings and incidentally helicals with more friction, so they did not need the infinity lock. Double focussing helicals and non-rotating lens fronts---Geradführung or 'straight-line movement' as it is called in German---did not become the rule until the 1950's. But by then most Leica photographers were so hardened in heir habits that they expected the lock. So lenses with a focusing tab, like the 35mm lenses, did start out with locks, which they did gradually lose. The old man from the Age of the 3.5cm Elmar Link to post Share on other sites More sharing options...
luigi bertolotti Posted March 11, 2009 Share #7 Posted March 11, 2009 Advertisement (gone after registration) GOOD, LARS !! I never thought of your simple and logic explanation on WHY they put the infinity lock ... too much time I don't use an old Elmar... ... of course, changing the f stops with lens free to rotate is really uneasy. Link to post Share on other sites More sharing options...
lars_bergquist Posted March 11, 2009 Share #8 Posted March 11, 2009 Yes Luigi, it does really take two hands. Now this was really brought home to me when I mounted my old 1960 5cm Elmar 2.8 on a M6 and tried to adjust the aperture with the camera at my eye ... I did also find that clip-on hoods were useless for this, as they are in the way of the fingers. Works with the camera hanging at your belly, but not at eye level! So I bought the cylindrical screw-in hood 12549 (that's the chrome version) which works just fine. The original front cap fits too! If you like this idea get one soon because the lens that goes with it---the Elmar-M 1:2.8/50mm has just been discontinued. The old man from the Elmar Age Link to post Share on other sites More sharing options...
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