Camera Mounts Sorted by Register

This is a list of known camera mounts (thanks to William-Jan Markerink, who provided almost all the data in this table. I have sorted the mounts in order of decreasing register (flange distance) to help see what adaptations might be feasible with correct infinity focus. Generally speaking, a lens might be adapted to bodies farther down the list; moving upward means that a simple adapter (one with no optical elements) is impossible for an unmodified camera and lens while retaining infinity focus.

Where the distances are the same, or very close, things might or might not work. For example, adapting a Leica R mount lens (distance 47mm) to a Nikon F mount (distance 46.5mm) leaves only 0.5mm space, which might be too thin to make a usable adapter. Close cases also require that the thread or bayonet of the lens must be small enough to fit entirely inside the mount of the body, and this list gives no information. That said, there are examples where an adapter between two mounts of exactly the same distance is possible, notably the Pentax K, for which Pentax M42 adapters are readily available. Presumably Pentax designed the K mount with this in mind. Where no adapter is possible, it is sometimes possible to modify a camera body with a mounting flange from some other system; look here for an example. Note that this isn't a cheap option unless you are a Leica owner. Of course, we can also modify the lens.

Where the distances are widely different, e.g. when adapting most medium-format lenses to most 35mm bodies, an adapter is usually feasible. Some manufacturers even encourage this, e.g. Pentax and Contax.

More modern cameras make things much more complicated with proprietary electronic lens/body connections for aperture control, autofocus, etc; even after buying or making a mechanical adapter, many features of the lens just won't work. Most lens mount conversions sacrifice autofocus, automatic exposure, or both. In some cases, even the camera's light-metering and focus confirm are crippled. One exception is Canon and Sigma SA mounts; apparently the electronic protocols reportedly match, and the lens register seems to be identical. Someone in China has apparently converted a Canon L-series lens to work on his Sigma digital SLR; there is a discussion of the relevant issues in this forum.

A more challenging approach is to build circuitry to translate between camera and lens; this is done in a somewhat pricey conversion of Contax N lenses for modern cameras with automatic features supported.

The same list is available in alphabetical order here.

Camera System Mount Type Register Diameter   Camera System Mount Type Register Diameter
Pentax Q bayonet 9.2   Asahiflex M37×1 thread 45.46 37
D-mount 0.625″×32tpi 12.29 15.88   ZM39 M39×26tpi 45.46 39
C-S mount 1″×32tpi thread 12.526 25.4   M42 screw M42×1 thread 45.46 42
Bolex H8RX 1″×32tpi thread 15.31 25.4   Mamiya/Sekor SX M42×1 thread 45.46 42
Nikon 1 bayonet 17 40   Pentax/Praktica M42×1 thread 45.46 42
C-mount 1″×32tpi thread 17.526 25.4   K-mount bayonet 45.46 44
Fujifilm X bayonet 17.7   Pentax K bayonet 45.46 44
Sony E bayonet 18   Contax S M42×1 thread 45.5 42
Micro Four Thirds bayonet 19.25   Petri bayonet 45.5 43
Canon EX1/2 VL camcorder bayonet 20   Contax/Yashica bayonet 45.5 48
Bolex breech 23.22   Pentina breech lock 45.5
Samsung NX bayonet 25.5   Ricoh breech mount 45.5
Pentax Auto 110 bayonet 27   Olympus OM bayonet 46 46
Leica M bayonet 27.95 44   Contarex bayonet 46
Konica Hexar RF bayonet 28   Nikon F bayonet 46.5 44
Narcissus M24×1 thread 28.8 24   Leica R bayonet 47 49
Canon screw M39×1 thread 28.8 39   Éclair CA-1 bayonet 48 46
Leica screw M39×26tpi 28.8 39   Contax N bayonet 48 55
Olympus Pen F bayonet 28.95   B4 bayonet 48
Contax G1 bayonet 29 44   HDTV 2/3″ B4 bayonet 48
Robot M26×0.5 thread 31 26   Icarex breech lock 48
Robot bayonet 31   Praktina breech lock 50 46
Hasselblad Xpan bayonet 34.27 46   Leica S bayonet 50
Contax RF dual bayonet 34.85 44   Adaptall bayonet(?) 50.7 54
Nikon rangefinder bayonet 34.85 49   Arri Maxi PL breech lock 52 64
1/2″ video bayonet 35.74   Arri PL breech lock 52 64
Alpa bayonet 37.8 42   Arriflex bayonet 52
Sony 1/2" Video bayonet 38   Werra breech lock 54 44.5
4/3 System digital bayonet 38.58 44   T2 mount M42×0.75 55 42
Argus 38mm thread 39 38   Topcon UV bayonet 55
Leitz Visoflex II, III Leica M bayonet 40 44   Panavision PV breech lock 57.15 49.5
Aaton PL-40 breech lock 40 50   Mamiya 7/7II bayonet 60 49
Konica Autoreflex bayonet 40.5 47   Mitchell BNCR breech lock 61.468 68
Konica F bayonet 40.5   Hasselblad H System bayonet 61.63
Miranda dual bayonet/screw 4-claw bayonet and 44×1mm screw mount 41.5   Leitz Visoflex I M39×26tpi 62.5 39
Canon R/FL/FD breech or bayonet 42 48   Mamiya 645 bayonet 63.3 62
Wrayflex M41.2×26tpi 42.05   Zeiss Ikon Panflex bayonet 64.5
Altix breech lock 42.5 34   Bronica ETRS bayonet 69
Yashica Pentamatic, Pentamatic II bayonet 43 47   Pentax 645 bayonet 70.87 61.2
Rectaflex bayonet 43.4   Rolleiflex SLX bayonet 74
Fujica X bayonet 43.5 49   Exakta 66 breech lock 74.1 60
Mamiya/Sekor E bayonet 43.5 49   Kiev 60/Kiev Six breech lock 74.1 60
Mamiya/Sekor CS bayonet 43.5   Pentacon 6 breech lock 74.1 60
Petriflex breech lock 43.5   Hasselblad 500/2000 bayonet 74.9 69
Minolta SR/MC/MD bayonet 43.72 41   Kilarscope M39×26tpi 78.8
Praktiflex M40×1 thread 44 40   Kowa Six/Super 66 breech lock 79
Canon EOS bayonet 44 54   Hasselblad 1000F/1600F multi start thread 82.1 78
Kiev 10,15 bayonet 44 42?   Kiev 88, Salut, Zenit 80 multi start thread 82.1 78
Paxette M39×1 thread 44   Zeiss Ikon Flektoskop, Flektometer screw 84.5
Sigma SA inner bayonet 44   Pentax 6×7 bayonet 84.95 72
Praktica bayonet 44.4   Bronica SQ bayonet 85 78
Argus bayonet 44.45   Kilarflex M39×26tpi 92.3
Minolta AF bayonet 44.5 49.7   Novoflex bayonet 100
Sony Alpha bayonet 44.5 49.7   Bronica S2A bayonet & 57×1 thread 101.7 57
Rolleiflex SL35 (QBM) bayonet 44.6 46   Rolleiflex SL66 bayonet 102.8
Exakta bayonet 44.7 38   Mamiya RZ bayonet 105 60
Topcon RE bayonet 44.7 38   Mamiya RB bayonet 112 60
Kodak Retina Reflex bayonet 44.7   Argus 33mm thread 33
Voigtländer Bessamatic bayonet 44.7   Bronica GS1 bayonet
Voigtländer Vitessa T bayonet 44.7          

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Stephen H. Westin swestin@earthlink.net
Last modified: Mon Jul 20 21:04:13 EDT 2015