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Leica Screw Mount to Leica M Bayonet Adapters
backward compatibility, hundreds of camera choices
New Cosina Voigtlander adapters are $55 each including the rear lens M cap. Specify the 28/90, 35/135, or 50/75 frameline combinations. For wider than 28 lenses, choose whatever adapter you like, since Leica does not offer automatic appearing framelines wide than 28mm. GENERIC 28/90 or 35/135 Adapters (no 50's) $32 each ORDER HERE
Need M Caps ? Generic quality M rear caps, $15 each or 3 for $40
Leica introduced their standardized interchangeable lens Leica 39mm screw mount in 1932 on the Leica Model C. The Leica M3 introduced the Leica M bayonet mount 1953. Both lens mounts are still in production in 2003. The M mount cameras feature 100% backward compatibility with screw mount lenses simply by mounting the Leica designed screw mount to Bayonet Mount adapter. This effectively turns a Leica screw mount lens into a Leica M bayonet lens.
Real world, the combination works great. The screw mount adapters tighten with use while still remaining easily removable. Just spin the adapter hand tight on the lens, then mount the lens on an M camera. This will automatically tighten up the adapter so that it stays put. To remove, unlock the lens from the camera body, and then use the camera body as an adapter wrench by turning the adapter off the lens. Before you ask, the reverse is not true. There is no adapter to use M lenses on screw mount bodies. Such an adapter would put the M lens too far from the film plane, making it capable only non rangefinder coupled extreme close-ups.
Screw Mount to Bayonet M Adapters:
Allow full and accurate rangefinder focusing (with RF coupled lenses)
Allow quick mounting and removal of the lenses, bayonet style. While you can turn the M bayonet camera into a screw mount camera simply by leaving the adapter no the body, most people dedicate one adapter for each lens for maximum convenience.
The proper lens frameline is automatically brought up in the finder on Leica M bodies, Hexar RF bodies, Leica CL or Minolta CL, or Minolta CLE bodies, automatically bring up lens framelines in the viewfinder. Of course you have to use the right adapter for the right lens and right body to get the right frameline.
IF you are new to rangefinders, framelines show approximately what each lens will show in a slide mount when at the minimum focus. Due to reasons too involved to discuss here, as the lens is focused to infinity it effectively has a slightly wider field of view than it does close-up. Between this optical phenomena and the smaller size of slides vs. the full negative, photogs have a fudge factor so they also get slightly more on the negative than what the framelines show.
The bottom line is screw mount lenses are more versatile than M mount lenses because they mount on more camera bodies.
Which Frameline in Which Camera with Which Adapter?
There are hundreds of different Leica screw mount bodies, most NOT made by Leica. Generically Leica mount cameras are called "Leica Copies," even if they are quite different Leica designs. By far more different cameras were made in Leica screw mount than any other interchangeable RF mount. As a result, non Leica made screw mount lenses are numerous and offer great variety. The two largest Japanese manufacturers of Leica screw mount lenses in the classic RF era were no less than Nikon and Canon.
All Leica M's (except the M1, MD and MDa) use a three frameline set which automatically shows the correct lens frameline once the lens in mounted. The M3 shows the 50, 90, and 135 framelines. The M2 shows the 35, 50, and 90 framelines. The M4, M5, and M4-2 show the 35, 50, 90, and 135 framelines (the 35 and 135 double up). framelines. The later M4-P, M6, M6TTL, M7, and MP with the standard .72 magnification finder all show six framelines by doubling them up (28/90, 35/135, 50/75). The exception are the later cameras with .85 finders which eliminated the 28 frame, and the .58 finders which eliminated the 135 frame. The Leica/Minolta CL show 40, 50, and 90 framelines. The Minolta CLE shows 28, 40, 90 framelines. The Hexar RF shows the 28/90, 35/135, 50/75 combination like the .72 Leica M finder. The Cosina Voigtlander R and R2 have manually selected 35, 50, 75, and 90 framelines. Most photogs still match up the lenses for their Bessas to the Leica framelines, since this makes it easier if you ever mount that lens on a Leica M.
IF your camera automatically brings up the lens' frame lines, you want to use the correct adapter for your camera / lens combination to show the proper frameline for that lens in the viewfinder. You can use the "wrong" adapter and still have full rangefinder coupling and accurate focusing. You will just have the wrong frameline showing-- but you can get around if your camera has a preview frameline lever. In practice it's a bit of a pain, but quite workable if you have only one adapter and a lot of screw mount lenses.
The widest automatically selected frameline is 28mm. That means it makes no difference you use with wider than 28 framelines, since you will be using the top mounted accessory finder anyway.
Used Leitz adapters sell for an average of $75 each. They are a number of variations. Most, but not all, of the Leitz adapters are engraved "Leitz." They are also labeled for their particular frameline. Earlier adapters made for the M3 might be labeled only 50 or 90 or 135. Rest assured they will also bring up the later 50/75, 90/28, 135/35 combinations on your M6.
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Revised: February 19, 2004 . Copyright © 2004 Stephen Gandy. All rights reserved. This means you may NOT copy and re-use the text or the pictures in ANY other internet or printed publication of ANY kind. Information in this document is subject to change without notice. Other products and companies referred to herein are trademarks or registered trademarks of their respective companies or mark holders.