Archived posting to the Leica Users Group, 1998/04/16
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]From the private mail that I have received, it seems that I have failed to make myself clear & am adding this bit of trivia. - ----------------------------- The early Leicas had fixed lenses (non-interchangable) and had to be matched to the individual bodies. In 1931/32 the bodies were all made to (I forget exactly but think a 28.xxxxmm) standard & a little "o" was added to the bodies lens flange & also to the now standardized lenses. Now the body focal plane to lens flange distance were all the same but it was too costly to produce all lenses to that same tolerance, so each lens was matched to a tube (mount) that corresponded with its true focal length and any errors were compensated for by the depth of focus of the majority of the lenses max. speed of f:3.5 . It was only the perfectionist (like the driver that has his engine blue printed) and dyno-tuned) that insisted on 100% accuracy. As a subject that already has been covered on the LUG --- 100% superimposition of the 2 rangefinder images is not really neccessary but since it is easy to obtain "Why Not"? When we go into the realm of the Summilux & Noctilux lenses, with close distance DOF of only inches --- then as Leica recommends: match the lens to the camera if you want accurarcy in inches with a rangefinder. By the way, for those of you that didn't know - An "aerial image" is one formed without the use of a ground glass (just in the air like a telescope). MMoss ======================================================== In a message dated 98-04-15 17:53:02 EDT, Marvin wrote: << Those of you that are seriously into fine tuning guns will know immediately what I am talking about but for the rest of you Leicaphiles, bare with me. All early Leica cameras had problems in matching a lens to its body, since the actual focal lengths varied ie (+ or - 1/10mm) and the bottom shells, not being die cast also varied. The solution to this, in the late '20s & early '30s was to have a PEEP HOLE built into the back of the camera where a loupe was attached ( quite similar to what Harold has just done) but since they were focusing on the aerial image rather than a ground glass, it was more accurate. After adjustments by adding shims ( .001/mm ) to the lens flange the peep hole was plugged and the pressure plate revolved to make it light tight. My exact figures might be off a tad but believe me - they were thin. When I worked professionally with Leicas back in the "50s to '70s, serious 35mm still photographers sent their Leica to Mel Pierce to have the lenses matched to the bodies. Although this really wasnt necessary after the die- cast bodies were made to closer tolerances, the lenses still had a variance in focal lengths. You can still see the # 0-9 stamped on many lenses - but that is another story already fully covered on the LUG last year. Even today, you will read about recommendations to have your high -speed lenses ( particularily the Noctilux) matched to your individual camera. I think it was either Browning or Winchester that got the idea of speeding up production by making closer tolerance parts that could then be interchanged. In my days of racing Porsches, an overhaul after each race was not unusual and the pistons & cylinders were graded in groups by 1/10,000" differences; the pluses balancing the minuses. Marvin Moss