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.

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

I have made the following changes:

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.


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.

Camera System Mount type Register Diameter Comments
1/2″ video bayonet 35.74   Most 3-chip SD video cameras not from Sony. From a Sandia National Labs technical report.
4/3 System digital bayonet 38.67 44 Designed by Olympus, this mount is apparently mechanically identical to the Olympus OM mount, but with a smaller register. An OM-to-4/3 adapter is just an extension tube.

Aaton PL-40 breech lock 40 50  
Adaptall bayonet(?) 50.7 54  
Alpa bayonet 37.8 42  
Altix breech lock 42.5 34  
Argus 33mm thread 41.9 33 Used for C3; register from the Argus Collectors' Group site.
Argus 38mm thread 39 38 Used for post-war Model 21
Argus bayonet 44.45   Used for C44
Arri Maxi PL breech lock 52 64
Arri PL breech lock 52 64  
Arriflex bayonet 52    
Asahiflex M37×1 thread 45.46 37 Predecessor to the Pentax with pentaprism finder and M42 mount. The later Pentax was badged “Asahiflex” in a few countries (Finland and South Africa, for starters) due to trademark complications.

B4 bayonet 48 (air)    
Bolex breech 23.22    
Bolex H8RX 1″×32tpi thread 15.31 25.4  
Bronica ETRS bayonet 69.0 ± 0.03   Measured to back of body (mount surface for film back); see service manual
Bronica GS1 bayonet     Register must be greater than that of Pentax 645 or Mamiya 645, as FotoDiox makes infinity-focus adapters to both of those cameras.
Bronica S2A bayonet & 57×1 thread 101.7 57  
Bronica SQ bayonet 85 78 Leaf shutter in each lens

C-mount 1″×32tpi thread 17.526 25.4 (0.69″)
C-S mount 1″×32tpi thread 12.526 25.4 According to Ikegami. Thread is also known as “1-32 UN 2A.”
Canon EOS bayonet 44 54  
Canon EX1/2 VL camcorder bayonet 20    
Canon R/FL/FD breech or bayonet 42 48 42.1mm according to this list, 42.00mm according to Wikipedia, 42.13mm according to a Japanese list that seems to have vanished from the Web. The Canon service manuals of the time specify a “42.14 Dial Gauge”, whatever that might be, to adjust the flange distance
Canon screw M39×24tpi 28.8 39 Known as Canon J mount and used only on the earliest cameras; most Canon rangefinders use Leica screw mount.
Contarex bayonet 46   No aperture ring on lenses; aperture set by control on body
Contax G1 bayonet 29 44 Autofocus rangefinder cameras from Kyocera
Contax N bayonet 48 55 Autofocus SLR cameras from Kyocera
Contax RF dual bayonet 34.85 44 Measured to outside of outer bayonet; see this page. Most lenses mount to inner bayonet and have no focusing helical; focus is in camera body. Lenses mounting to the outer bayonet (usually longer lenses) have focusing capability.
Contax S M42×1 thread 45.5 42 This post-WWII product from Zeiss in Jena (Soviet sector) actually originated the ubiquitous M42 mount made famous by Pentax.
Contax/Yashica bayonet 45.5 48 This mount is very similar to the Pentax K bayonet; enough so that, like the mounts of the Retina Reflex and Voigtländer Bessamatic, modification is possible for compatibility

D-mount 0.625″×32tpi 12.29 15.88 Mainly for 8mm movie cameras

Éclair CA-1 bayonet 48 46  
Exakta 66 breech lock 74.1 60 Same as Pentacon 6 and Kiev 60.
Exakta bayonet 44.7 38 Fundamentally identical to Topcon RE mount, but aperture coupling is different.

Fujica X bayonet 43.5 49 35mm film cameras; discontinued in 1985
Fujifilm X bayonet 17.7   Mirrorless digital cameras

Hasselblad 1000F/1600F multi start thread 82.1 78 Focal-plane shutter (no shutter in lens)
Hasselblad V System bayonet 74.9 69 Leaf shutter inside each lens; used on Hasselblad 500/2000.
Hasselblad H System bayonet 61.63    
Hasselblad Xpan bayonet 34.27 46  
HDTV 2/3″ B4 bayonet 48    

Icarex breech lock 48   Aperture ring on camera, not lens.

K-mount bayonet 45.46 44  
Kiev 10,15 bayonet 44? 42?  
Kiev 60/Kiev Six breech lock 74.1 60 Same as Exakta 66 and Pentacon 6
Kiev 88, Salut, Zenit 80 multi start thread 82.1 78 Very similar to Hasselblad 1000F/1600F; may or may not fit
Kilarflex M39×26tpi 92.3   Reflex attachment like Visoflex or Flektoskop for rangefinder camera. Available to mount on either Leica M39 or Contax RF; I think all the lenses used M39 mount.
Kilarscope M39×26tpi 78.8   Reflex attachment like Visoflex or Flektoskop for rangefinder camera. Unlike the Kilarflex, provides an eye-level finder.
Kodak Retina Reflex bayonet 44.7   Very similar to Voightländer Bessamatic mount. Kodak used the same mount on their Kodak Instamatic Reflex.
Konica Autoreflex bayonet 40.5 47 According to this page and this one. Markerink’s original list had it as 40.7.
Konica F bayonet 40.5    
Konica Hexar RF bayonet 28.00mm ± 0.03mm (pressure plate rails)
27.76mm (film rails)
  Designed for compatibility with Leica M lenses, but nominal distances are slightly different.
Reflex Korelle 40.5 × 0.75 thread 77.5 40.5 Register according to AllPhotoLenses; thread size from Camerapedia.
Kowa Six/Super 66 breech lock 79    

Leica M bayonet 27.80 44 Measured to pressure-plate rails. 27.76 to film rails. See this page for a discussion of the subtleties.
Leica R bayonet 47 49 Used by Leitz's 35mm SLR cameras: Leicaflex and Leica R series
Leica S bayonet 53   Register mentioned in passing on a Luminous Landscape forum. Choice of lenses with leaf shutter or without.
Leica screw M39×26tpi 28.8 39 This and the Visoflex mount are sometimes mistaken for M39×1mm, a tiny difference, but enough to cause problems with some non-Leica M39 lenses.
Leitz Visoflex I M39×26tpi 91.30 39 28.8 body + 62.5 housing → 91.3 total
Leitz Visoflex II, III Leica M bayonet 68.80 44 27.8 body + 41 housing → 68.8 total; discussion in a Leica forum.

M42 screw M42×1 thread 45.46 42 Used by Contax S, Pentax, Praktica, and many Yashica, Chinon, Cosina, Ricoh, and Soviet cameras.
Mamiya 7/7II bayonet 57.85 49 Register from a forum post on Luminous Landscape. Diameter according to this measurement. Shown as 62mm here.
Mamiya 645 bayonet 63.3 62  
Mamiya/Sekor CS bayonet ~43.5mm   Forerunner of Mamiya E mount
Mamiya/Sekor E bayonet ~43.5mm 49 Used in the Mamiya/Sekor ZE series cameras. Electronic upgrade of Mamiya CS mount with only partial compatibility.
Mamiya RB bayonet 112.00 60 111.00 according to this message on
Mamiya RZ bayonet 105.00 60 108.00 according to this message on
Mamiya/Sekor SX M42×1 thread 45.46 42 Modification of the M42 mount to enable full-aperture metering. Usually requires modification to mount on M42 cameras.
Micro Four Thirds bayonet 19.25 38 From Wikipedia
Minolta AF bayonet 44.5 49.7 variously listed elsewhere as 44.5, 44.6, 44.7; Konica/Minolta’s digital SLRs were taken over by Sony, who uses the same mount.
Minolta SR/MC/MD bayonet 43.72 +0.01 -0.02 41 Measured (I think) to pressure plate rails: see this service manual for specifics.
43.7 +0.02, -0 according to this page.
Minolta V bayonet 38   Used for the Vectis SLRs for APS film, as well as the Dimage RD-3000 DSLR. From CameraWiki.
Miranda dual bayonet/screw 4-claw bayonet and 44×1mm screw mount 41.5   41.46 according to this page. Apparently the M44 thread originated in first Miranda of 1954, and was retained for compatibility when a new bayonet was introduced. Starting in 1974, the "TM" models used M42, and a Miranda-branded K-mount SLR was sold in the U.K.
Mitchell BNCR breech lock 61.468 68 (1966)

Narcissus M24×1 thread 28.8 24  
Nikon 1 bayonet 17 40  
Nikon F bayonet 46.5 44  
Nikon S bayonet 34.54 49 Identical to Contax rangefinder mount, but with slightly different lens register. Diameter given as 44mm here.
Novoflex bayonet 100    

Olympus OM bayonet 46 46  
Olympus Pen F bayonet 28.95    
Opema 38mm thread 28.8   From a Brazilian site. Image was 24×32mm.

Camera System Mount type Register Diameter Comments
Panavision PV breech lock 57.15 49.50 (1972)
Paxette M39×1 thread 44    
Pentacon 6 breech lock 74.1 60 Identical to Exakta 66 and Kiev 60.
Pentax 6×7 bayonet 84.95 72 (74.10?)
Pentax 645 bayonet 70.87 61.2  
Pentax Auto 110 bayonet 27    
Pentax/Praktica M42×1 thread 45.46 42 add film thickness, and get 45.50mm...
Pentax K bayonet 45.46 44 Register identical to Pentax M42 mount
Pentax Q bayonet 9.2    
Pentina breech lock 54.95   ± 0.03, according to the Carl Zeiss Jena service manual
Petri bayonet 45.5 43  
Petriflex breech lock 43.5    
Praktica bayonet 44.4    
Praktiflex M40×1 thread 44.0 40  
Praktina breech lock 50 46  

Rectaflex bayonet 43.4    
Ricoh breech mount 45.5   As best I can tell, this mount was exclusive to the Ricoh 999 rangefinder, also sold as the Anscomark M.
Robot M26×0.5 thread 31 26 used in all models except Royal
Robot bayonet 31   Robot Royal models only
Rolleiflex SL35 (QBM) bayonet 44.6 46 44.5mm according to Schneider, 44.7 according to another list that has since disappeared from the Web, 44.46 according to Wikipedia
Rolleiflex SL66 bayonet 102.8   according to this message on
Rolleiflex SLX bayonet 74.00    

Samsung NX bayonet 25.50    
Sigma SA inner bayonet 44   Similar to Pentax K, but incompatible. Rumor from China has the Sigma mount using the same electrical signals as the Canon EOS mount, with which it shares a register of 44.0 mm.
Sony 1/2" Video bayonet 38   Canon designation is SY14
Sony Alpha bayonet 44.5 49.7 Variously listed elsewhere as 44.5, 44.6, 44.7; identical to Minolta AF mount.
Sony E bayonet 18    

T2 mount M42×0.75 55 42 Also T-mount, Sigma YS. T stands for "Tamron".
Topcon RE bayonet 44.7 38 Identical to Exakta, but with different mechanism for automatic diaphragm.
Topcon UV bayonet 55   Used on leaf-shutter cameras with shutter behind the lens.

Voigtländer Bessamatic bayonet 44.7   This is a leaf-shutter camera, but designed with the shutter behind the lens, so the entire lens can be removed and used elsewhere. The aperture ring is part of the camera, not part of the lens. Someone will sell you a Nikon F adapter for this mount that includes an aperture control ring. The Bessamatic mount is so similar to that of the Kodak Retina Reflex that apparently it is possible to modify a lens to fit both cameras.
Voigtländer Vitessa T bayonet 44.7   A variant of the Deckel mount,but including the aperture control ring in the lens, rather than in the body. Also used on the Braun Colorette.

Werra breech lock 54 44.5 ± 0.03 according to the Carl Zeiss Jena service manual
Wrayflex M41.2×26tpi 42.05    

Yashica Pentamatic, Pentamatic II bayonet 43.00 47 This mount predates the M42-mount Yashica SLR’s, which were introduced in 1962. Judging by the photos of Exakta and M42 adapters found in the manual, the register is significantly less than the 45.46mm of the M42 mount. Not to be confused with the shared Contax/Yashica bayonet mount, which has a register similar to that of the M42 mount.

ZM39 M39×26tpi 45.46 39 An oddity that apparently uses the Leica thread, but with the same register as M42. Used on Zenit 1, Zenit S, Zenit 3, Zenit 3M, and Kristall.
Zeiss Ikon Flektoskop, Flektometer screw 119.35   A rangefinder-to-SLR converter à la Leitz Visoflex: 34.85 body + 84.5 housing → 119.35
Zeiss Ikon Panflex bayonet 99.35   total: A rangefinder-to-SLR converter à la Leitz Visoflex: 34.85 body + 64.5 housing → 99.35.
Uses the large outer Contax bayonet to mount to camera and provides another to mount the lens on the front.

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Stephen H. Westin
Last modified: Thu Feb 11 06:30:39 EST 2016