Lens mount

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A Leica R series teleconverter, with the female side of the Leica R bayonet mount. This side is also used on the camera body.
A Leica R series teleconverter, with the female side of the Leica R bayonet mount. This side is also used on the camera body.
…and the male side.
…and the male side.

A lens mount is an interface — mechanical and often also electrical — between a photographic camera body and a lens. It is confined to cameras where the body allows interchangeable lenses, most usually the single lens reflex type or any movie camera of 16 mm or higher gauge. Lens mounts are also used to connect optical components in instrumentation that may not involve a camera, such as the modular components used in optical laboratory prototyping which join via C-mount or T-mount elements.

A lens mount may be a screw-threaded type, a bayonet-type, or a friction lock type. Modern still camera lens mounts are of the bayonet type, because the bayonet mechanism precisely aligns mechanical and electrical features between lens and body. Screw-threaded mounts are fragile and do not align the lens in a reliable rotational position, yet types such as the C-mount interface are still widely in use for other applications like video cameras and optical instrumentation.

Bayonet mounts generally have a number of tabs (often three) around the base of the lens, which fit into appropriately sized recesses in the lens mounting plate on the front of the camera. The tabs are often "keyed" in some way to ensure that the lens is only inserted in one orientation, often by making one tab a different size. Once inserted the lens is fastened by turning it a small amount. It is then locked in place by a spring-loaded pin, which can be operated to remove the lens.

Lens mounts of competing manufacturers (Nikon, Canon, Contax/Yashika, Pentax, etc.) are almost always incompatible. Many allege that this is due to the desire of manufacturers to "lock in" consumers to their brand. However, since there are other differences between manufacturers — specifically the flange focal distance from the lens mount to the film or sensor — one would not want to mount a lens which wasn't specifically designed for their type of camera, at least not without an adapter to correct the spacing.

In movie cameras, the two most popular mounts in current usage on professional 35 mm cameras are Arri's PL mount and Panavision's PV mount. The Panavision mounts are exclusively used with Panavision lenses, and thus are only available on Panaflex cameras or third-party cameras "Panavised" by a Panavision rental house, whereas the PL mount style is favored with most other cameras and cine lens manufacturers. Both of these mounts are held in place with locating pins and friction locking rings. Other mounts which are now largely historical or a minority in relation to current practices are listed below.

Contents

[edit] List of lens mount types

These types are organized by category; find details in the section that follows.

[edit] Stills

[edit] Cine

[edit] Industrial

[edit] List of lens mounts

This list of lens mounts is ordered by flange focal distance, from shortest to longest. It includes both still photography and movie lens mounts.

Mount name Camera type Mount type Flange focal distance
D mount 8 mm movie and CCTV Screw (0.625 inch × 32 TPI) 12.29 mm
CS mount 16 mm movie and CCTV Screw (1 inch × 32 TPI) 12.52 mm
C mount 16 mm movie and CCTV Screw (1 inch × 32 TPI) 17.526 mm (0.69 inches)
Canon EX Camcorder Bayonet 20 mm
Bolex 16 mm movie Breech lock 23.22 mm
Leica M bayonet 35 mm still Bayonet 27.80 mm
Canon screw mount 35 mm still Screw (M39 × 1 mm)
Leica M39 screw mount 35 mm still, enlargers Screw (M39 × 26 TPI) 28.80 mm
Narcissus 35 mm still Screw (M24 × 1 mm) 28.80 mm
Olympus Pen F 35 mm half-frame still Bayonet 28.95 mm
Hasselblad Xpan 35 mm panoramic still Bayonet 34.27 mm
Four Thirds digital still Bayonet 38.67 mm
Aaton universal 16 mm movie Breech lock 40 mm
Canon R 35 mm still Breech lock 42 mm
Canon FL 35 mm still Breech lock 42 mm
Canon FD 35 mm still Breech lock 42 mm
Fujica-X 35 mm still Bayonet 43.50 mm
Minolta MC/MD 35 mm still Bayonet 43.50 mm
Petriflex 35 mm still Breech lock 43.50 mm
Canon EF 35 mm still Bayonet 44 mm
Canon EF-S APS-C digital still Bayonet 44 mm
Sigma SA 35 mm still Bayonet 44 mm
Paxette 35 mm still Screw (M39×1 mm) 44 mm
Praktica B 35 mm still Bayonet 44.40 mm
Minolta AF 35 mm still Bayonet 44.50 mm
Rolleiflex SL35 35 mm still Bayonet 44.60 mm
Exakta, Topcon 35 mm still Bayonet 44.7 mm
Pentax K 35 mm still Bayonet 45.46 mm
M42 lens mount or Praktica 35 mm still Screw (42 mm×1mm) 45.46 mm
Olympus OM 35 mm still Bayonet 46 mm
Yashica/Contax 35 mm still Bayonet 45.50 mm
Nikon F-mount 35 mm still Bayonet 46.5 mm
Leica R 35 mm still Bayonet 47 mm
Contax-N 35 mm still Bayonet 48 mm
Praktina 35 mm still Breech lock 50 mm
Arri standard 35 mm and 16 mm movie Tab lock 52 mm
Arri bayonet 35 mm and 16 mm movie Bayonet 52 mm
Arri PL 35 mm and 16 mm movie Breech lock 52 mm
T-mount or T-thread 35 mm still Screw (M42×0.75) 55 mm
PV mount 35 mm movie Breech lock 57.15 mm
BNCR mount 35 mm movie Breech lock 61.468 mm
Mamiya 645 Medium format Bayonet 63.30 mm
Leitz Visoflex II/III 35 mm still Bayonet (Leica M) 68.80 mm
Pentax 645 Medium format still Bayonet 70.87 mm
Pentacon Six Medium format still Breech lock 74.10 mm
Pentax 6x7 Medium format still Bayonet 84.95 mm
Leitz Visoflex I 35 mm still Screw (M39×26 TPI) 91.30 mm
Mamiya RZ Medium format still Bayonet 105 mm
Mamiya RB Medium format still Bayonet 112 mm
Mamiya 7/7II Medium format still Bayonet ~60 mm ???
Kowa Six/Super 66 Medium format still breech lock 79 mm
Hasselblad Medium format still Bayonet 74.9 mm
Bronica S2A Medium format still Bayonet & 57×1 thread 101.7 mm
Rolleiflex SL66 Medium format still Bayonet 102.8 mm

[edit] Secondary lens mount

Secondary lens refers to a multi-element lens mounted either in front of a camera's primary lens, or in between the camera body and the primary lens.

(D)SLR camera & interchangeable-lens manufacturers offer lens accessories like extension tubes and secondary lenses like teleconverters; which mount in between the camera body and the primary lens, both using and providing a primary lens mount.

Canon PowerShot A and Canon PowerShot G cameras have a built-in or non-interchangeable primary (zoom) lens; and Canon has "conversion tube" accessories available for some Canon PowerShot camera models which provides either a 52mm or 58mm "accessory/filter" screw thread. Canon's close-up, wide- (WC-DC), and tele-conversion (TC-DC) lenses have 2, 3, and 4-element lenses respectively, so they are multi-element lenses and not diopter "filters".

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