Alphabetical List of Camera Mounts

This is basically a reformatting of the wonderful list published by William-Jan Markerink. There are several other extensive lists; here are a few.

• The Film Centre.
• The Italian Film Photography site
• The Lens Lab from Jim Mayes (in Japanese)
• Wikipedia

There is also a wonderful page with photographs of different mounts.

• Added the B4 mount for 2/3″ HDTV (and, I think, other video with 2/3″ sensors).
• Added decimal places to the C-S register distance.
• Noted that the Canon EX1 and EX2 are camcorders.
• Added the Nikon rangefinder mount, and relabeled the SLR mount “Nikon F”.
• Confused myself about Minolta mounts. Apparently the old MD mount is around 44.72mm, but the newer autofocus mount is listed as 44.5, 44.6, and 44.7, depending on where you look. I thought I had found the AF mount, but the camera involved was an MD mount.
• Added a reference to the Sigma SA mount, which resembles the Pentax K, but with different meter, aperture, and autofocus connections, and with a smaller register distance.
• Clarified the Icarex mount situation. Some later models used the M42 thread mount. I am assuming that the “bayonet” Icarex mount is the same as the “breech lock” mentioned in the Markerink and KineOptics lists.
• Altered the Miranda entries. I believe there was only one mount and that the auxiliary screw mount has a diameter of 44mm, not 42 or 46. The latter seems to be a filter mount. See this page and this one for more info.
• Added the Yashica Pentamatic mount, and revised Konica Autoreflex and Contax rangefinder data.
• Added the Hasselblad Xpan (actually a Fuji product, but sold by Hasselblad)
• Added the Contax N autofocus SLR mount.
• Added the Sony Alpha mount, which is the same as the Minolta AF mount.
• Added information from the Dresden Cameras site by Michael Sorms.
• Filled in more entries in the second column (“Mount type”).
• Resolved several dead links.
• Added several of the new mounts for digital cameras with electronic viewfinders only.
• Added Pentax Auto 110 mount.
• Revised the Miranda entry again, thanks to Andrew Fildes of Australia.
• Corrected the Samsung NX entry; thanks to Greg Clark for the correction
• Added mounts for mirrorless digital cameras: Nikon 1, Pentax Q, and Samsung NX
• Added the Argus C3 thread mount (diameter only) and the Rolleiflex SLX mount, as well as a few diameters.
• Added the Hasselblad H System and Leica S, though there is only speculation as to the actual register of the latter.
• Updated information on the Aaton mount and filled out information for several other cine mounts, courtesy JP Beauviala.
• Added the Reflex Korelle.
• Began to add mount diameters where info is available.
• Marked each entry according to the original format of the lens/camera combination:

  35mm full-frame is yellow

  Smaller formats are blue

  Larger formats are green

  Cinema and video formats are white.

• Corrected register for Four Thirds System.
• Corrected register for Leica M.
• Added paragraphs about some of the pitfalls of adapting lenses.
• Corrected register for Leica S and Mamiya 7.
• Added register for Argus C3.
• Added Minolta V and Opema mounts.

The same list is available sorted in order of register distance here.

Basic Issues with Adapting Lenses

At first glance, adapting a lens to fit a camera seems quite straightforward, if the two registers relate in the correct way. That is, the new camera has a register distance less than that of the camera originally intended for the lens. Unfortunately, several things can get in the way.

First, lens mounts for movie cameras are generally designed so the lens extends quite far into the camera behind the flange surface. I suspect this is done to get a much stiffer, stronger connection between lens and camera. Lenses for SLR still cameras don't extend very far into the camera, because space is needed for the mirror to move.

Second, the diameter of the mount matters: your lens might be too fat to attach at the correct register.

Third, some lens mounts, notably the Contax rangefinder, put the focusing mechanism in the camera body; most adapters or modifications will need to include a means to focus the lens.

Fourth, some cameras (e.g. Zeiss Contaflex, Kodak Retina IIIc) don't let you remove the entire lens, but offer interchangeable front elements to provide different focal lengths. Needless to say, adapting such half-lenses to another camera has little chance of giving any useful result. I believe the interchangeable elements for the Contaflex were all named “Pro-Tessar”.

Finally, some lens mounts depend on the camera body to set the aperture; the Contarex and Icarex mounts fall in this category, as does the obscure mount of the Kiev 10 and 15. Any adapter will need to provide some mechanism to control aperture. An increasing number of modern lenses also fall into this category. A few mounts (e.g. Pentax 110 and Canon SD lenses for the Demi C) put the iris in the body, so the lenses lack it.

Functionality

Back in the 1930s, the only connection between lens and camera body was structural; the lens mount simply had to hold the lens at a precise distance from the film. As time went on, however, things got more complicated. First came automatic stop-down of the lens aperture for SLRs: the photographer could focus and frame the shot with lens wide open, and as soon as the shutter release was pressed, the lens would stop down to an aperture set beforehand. Then, as SLRs acquired through-the-lens metering systems, the lenses of some cameras had a mechanism to signal what aperture had been selected. After that came automatic exposure, and the camera needed to control the lens aperture (and to know the aperture range of the lens). Finally came automatic focus: the camera could focus the lens, mechanically or electrically.

These more sophisticated connections, however, are far harder to adapt between different lens mounts. Once you have built an adapter (or modified mount) to connect a lens from system A to camera body B, you still lack the connections to make automatic aperture, exposure, and focusing work. Typically this means that many functions are lost; you stop the lens down manually, use manual exposure, etc. This can run afoul of the electronics of modern SLRs; Canon SLR's, for example, usually require a chip in the adapter if you want to use the autofocus system as a guide to focussing manually. Realistically, this full-manual functionality is all that can be hoped for, given the diversity of mechanisms and the lack of space to build any sort of lever arrangement.

These difficulties exist even where such adapters were planned as part of the mount design; Pentax, for example, offered an adapter to use M42 lenses on the K bayonet, but none of the automation works. The Contax/Yashica bayonet is so similar to the Pentax K that apparently a bit of work with a file or Dremel tool can get one to mount on the other, but the aperture mechanisms are completely different.

One happy exception is the Rollei/Voigtländer QBM mount used in the Rolleiflex SL35 and kin; this uses a stop-down pin copied from the M42 mount, so an M42 lens on a Rollei with the factory-supplied adapter retainss the original aperture function of the lens. Another is the Sigma SA mount, which copies the electronic protocol of the Canon EF mount, as well as its register distance. Apparently it is possible to modify a Canon lens with a Sigma mount, or a Sigma body with a Canon mounting flange, and have full automation and autofocus. It is also possible, in principle, to build electronics to convert between lens protocols for two systems; a company called Conurus offers such a modification for Contax N lenses to mount on Canon EF or Sigma bodies.