Archived posting to the Leica Users Group, 1996/11/24
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At 02:04 PM 11/24/96 -0800, Alan Bearden wrote:
>The Leica screw mount is 39mm x 1mm (thread); not 26 tpi. I just measured
>several using a comparison microscope.
Well, the bulk of my references are at the office, and I'm at the house, so
a quick scan could only locate one. Peter Dechert, the great scholar of the
Canon RF cameras (and also a scholar of things Leica), wrote on p. 15 of his
CANON RANGEFINDER CAMERAS 1933 - 1968, in explanation of why early Canon and
Nikon LTM lenses will sometimes not mount on Leica cameras:
... both Canon and Nippon Kogaku engineers believed that the Leitz
flange pitch was exactly 1.0mm, when in fact it is 26 threads to the
inch.
I have a copy of the original Leica lens-mount patent, somewhere, and
Barnack set out therein that the mount was 39mm by 26 tpi. I believe Emil
Keller has a picture of it in his HISTORY OF THE 35mm CAMERA.
Marc
msmall@roanoke.infi.net FAX: +540/343-7315
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