I was digging about in my collection of Leitz reflex housings (Prewar PLOOT to the Viso III) to answer some questions for one of our List members when I came across the following:
Rollei-werke F&H 205 550 DGOGEThis is an adapter allowing the fitment of Leica thread-mount and enlarging lenses, most of which are in Leica thread-mount, to the SL35 family. You lose infinity focus but it is a grand and lightweight means for getting some good macro results. Mine is New In Box (though I have used it several times, so I guess it is now just E condition!). What is odd is that the box is marked:
Übergangsadaper M39x1.Wow! What a MAJOR boo-boo. If there is one thing I know intimately, it is true Leica thread-mount. And true LTM is NOT M39 (39mm by 1mm DIN thread). It is 39mm by 26 turns-per-inch Whitworth thread. Yeah, as the old Benson & Hedges cigarette ads ran, "just a silly millimeter longer". Trying to mount an LTM lens on an M39 mount is going to give you major gastric upset. My adapter IS in true LTM -- I know: I have used it with a couple of different LTM lenses. It is just mismarked.
FED made this error before the War as these Proletarian Heros of Soviet Labor (well, actually the kids of those killed off by the Cheka and then the NKVD) could not conceive of a sound Metric nation like Germany ever making a fitment in mixed systems. FED got it right from 1945 onwards. But then Canon in Japan made the same mistake, and only fixed THEIR problem immediately before the outbreak of the Korean Police Action. Since 1949, LTM has meant 39mm by 26 turns-per-inch Whitworth, and so be it.
Leitz was a microscope company and Whitworth was the thread specifically designed for scientific and technical applications, so it was the norm for microscopes almost up to our own time, and there are still some holdovers such as "the Royal Screw". Barnack when selecting his mount's dimensions went with the reality that he had a factory full of machine tools set up to produce Whitworth threads in inches. Whitworth, incidentally, is probably the finest thread design to date: it will not come unthreaded without a decent amount of force, unlike SAE and DIN. But it is a lot more expensive to produce.
I believe this to be the only case of mismarking I have yet found on a Rolleiflex product.
Marc msmall@xxxxxxxxxxxx Cha robh bàs fir gun ghràs fir! --- Rollei List - Post to rollei_list@xxxxxxxxxxxxx - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' in the subject field OR by logging into www.freelists.org - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with 'unsubscribe' in the subject field OR by logging into www.freelists.org - Online, searchable archives are available at //www.freelists.org/archives/rollei_list
