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 for modern cameras.

Camera System Mount Type Register Diameter   Camera System Mount Type Register Diameter
Pentax Q bayonet 9.2   Pentax K bayonet 45.46 44
D-mount 0.625″×32tpi 12.29 15.88   K-mount bayonet 45.46  
C-S mount 1″×32tpi thread 12.526 25.4   Contax S M42×1 thread 45.5 42
Bolex H8RX 1″×32tpi thread 15.31 25.4   Contax/Yashica bayonet 45.5  
Nikon 1 bayonet 17     Mamiya ZE bayonet 45.5  
C-mount 1″×32tpi thread 17.526 25.4   Pentina breech lock 45.5  
Fujifilm XF bayonet 17.7     Petri bayonet 45.5  
Sony E bayonet 18     Ricoh breech mount 45.5  
Micro Four Thirds bayonet 19.25     Olympus OM bayonet 46 46
Canon EX1/2 VL camcorder bayonet 20     Contarex bayonet 46  
Bolex breech 23.22     Nikon F bayonet 46.5 44
Samsung NX bayonet 25.5     Leica R bayonet 47  
Pentax Auto 110 bayonet 27     B4 bayonet 48 (air)  
Leica M bayonet 27.95 44   Contax N bayonet 48  
Konica Hexar RF bayonet 28     Eclair bayonet 48  
Narcissus M24x1 thread 28.8 24   HDTV 2/3″ B4 bayonet 48  
Canon screw M39x1 thread 28.8 39   Icarex breech lock 48  
Leica screw M39x26tpi 28.8 39   Leica S bayonet 50?  
Olympus Pen F bayonet 28.95     Praktina breech lock 50 54
Contax G1 bayonet 29     Adaptall bayonet(?) 50.7 54
Hasselblad Xpan bayonet 34.27     Arri PL breech lock 52 64
Nikon rangefinder bayonet 34.85 49   Arriflex bayonet 52  
Contax RF dual bayonet 34.85     Arri Maxi PL breech lock 52  
Alpa bayonet 37.8 42   T2 mount M42x0.75 55 49.5
4/3 System digital bayonet 38.58 44   Topcon UV bayonet 55 49
Leitz Visoflex II, III Leica M bayonet 40 44   Panavision PV breech lock 57.15 68
Aaton PL-40 breech lock 40 50   Mamiya 7/7II bayonet ∼60  
Konica Autoreflex bayonet 40.5     Mitchell BNCR breech lock 61.468 39
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 M39x26tpi 62.5  
Canon R/FL/FD breech or bayonet 42 48   Mamiya 645 bayonet 63.3  
Wrayflex M41.2×26tpi 42.05     Zeiss Ikon Panflex   64.5  
Altix breech lock 42.5 34   Bronica ETRS bayonet 69  
Yashica Pentamatic, Pentamatic II bayonet 43     Pentax 645 bayonet 70.87  
Rectaflex   43.4     Rolleiflex SLX bayonet 74  
Fujica X bayonet 43.5 49   Exakta 66 breech lock 74.1  
Petriflex breech lock 43.5     Kiev 60/Kiev Six breech lock 74.1  
Minolta SR/MC/MD bayonet 43.72 41   Pentacon 6 breech lock 74.1  
Canon EOS bayonet 44 54   Zenit 80 multi start thread 74.1  
Kiev 10,15 bayonet 44? 42?   Hasselblad 500/2000 bayonet 74.9  
Paxette M39x1 thread 44     Kilarscope   78.8  
Praktiflex M40x1 thread 44     Kowa Six/Super 66 breech lock 79  
Sigma SA inner bayonet 44     Hasselblad/Kiev88 multi start thread 82.1  
Praktica bayonet 44.4     Kiev 88 multi start thread 82.1 78
Praktica bayonet 44.4     Zeiss Ikon Flektoskop, Flektometer screw 84.5  
Argus bayonet 44.45     Pentax 6x7 bayonet 84.95  
Minolta AF bayonet 44.5 49.7   Bronica SQ bayonet 85 57
Sony Alpha bayonet 44.5 49.7   Kilarflex   92.3  
Rolleiflex SL35 (QBM) bayonet 44.6 46   Novoflex   100  
Exakta/Topcon bayonet 44.7     Bronica S2A bayonet & 57x1 thread 101.7  
Kodak Retina Reflex bayonet 44.7     Rolleiflex SL66 bayonet 102.8  
Topcon RE bayonet 44.7     Mamiya RZ bayonet 105  
Voigtländer Bessamatic bayonet 44.7     Mamiya RB bayonet 112  
Asahiflex bayonet 45.46 37   Argus 33mm thread    
ZM39 M39x26tpi 45.46 39   Bronica GS1 bayonet    
M42 screw M42x1 thread 45.46 42   Schneider M26x0.5    
Pentax/Praktica M42x1 thread 45.46 42          

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Stephen H. Westin
Last modified: Fri May 15 11:55:42 EDT 2015