Archived posting to the Leica Users Group, 1996/09/13
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]In <Pine.SCO.3.91.960912141538.6399B-100000@mark.mwa.org>, on 09/12/96 at 02:17 PM, Thomas Knoles <tgk@mwa.org> said: >My 50mm Summicron-M has the number "22" engraved sideways in small >characters on the focusing ring, just at the end of the metric focusing >scale. >Can anyone out there tell me what it means? >Tom Knoles >tgk@mwa.org Although the question has already been well answered I thought there was another question posted, 'why' but can't seem to find it if it existed. Anyway, for the 'why', I consulted The Leica & Leicaflex Way, Andrew Matheson. and find it said: "This may be important in highly accurate scientific work and also in exact photo-surveying." An indication that Leitz viewed the Leica as more than 'just a camera' Earlier lenses would have the focal length, to the nearest 1/10 mm hand scribed on the inner barrel. This was used to ensure that the lens was mated with a matching focusing helicoid to ensure proper focus coupling with the rangefinder. Oh yes, if your 90 mm lens is inscribed 95 on the barrel next to the focus index mark, it means its really 89.5 mm. I was so confused about that for a while. As an aside, I believe the computed focal length of a lens is not always the nominal focal length. Somewhere in the dusty recesses of my memory I recall the first 50 mm Summicron was computed for a focal length of 51.9 mm. A tip of the hat to anyone who knows the story on this. Regards Dennis Experience is a tough teacher. It gives the test before the lesson. -unknown http://users.deltanet.com/~dwp