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/Yashica, 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 |
List of lens mount types
These types are organized by category; find details in the section that follows.
|
|
List of lens mounts
This list of lens mounts is ordered by flange focal distance, from shortest to longest. It includes both digital, still photography and movie lens mounts.
| OEM model line(s) |
Interchangeable type name |
Frame size |
Camera type |
Throat or thread diameter |
Mount thread pitch |
Mount type |
Flange focal distance |
|---|---|---|---|---|---|---|---|
| D mount | 8 mm | movie and CCTV | 0.625 inch | 32 TPI | Screw | 12.29 mm | |
| CS mount | 16 mm | movie and CCTV | 1 inch | 32 TPI | Screw | 12.52 mm | |
| C mount | 16 mm | movie and CCTV | 1 inch | 32 TPI | Screw | 17.526 mm (0.69 inches) | |
| Canon EX | Camcorder | Bayonet | 20 mm | ||||
| Olympus E-P1, Panasonic G1, GH1, GF1 | Micro Four Thirds | digital still | ~38mmA[›] | Bayonet | ~20 mm | ||
| Bolex | 16 mm | movie | Breech lock | 23.22 mm | |||
| Leica M bayonet | 35 mm | still | 44 mm | Bayonet | 27.8 mm | ||
| Canon screw mount | 35 mm | still | M39 | 1 mm | Screw | ||
| Leica M39 screw mount | 35 mm | still, enlargers | M39 | 26 TPI | Screw | 28.8 mm | |
| Narciss | 16 mm | still | M24 | 1 mm | Screw | 28.8 mm | |
| Olympus Pen F | 35 mm half-frame | still | Bayonet | 28.95 mm | |||
| Contax G | 35 mm | still | Breech lock | 29.00 mm | |||
| Hasselblad Xpan | 35 mm panoramic | still | Bayonet | 34.27 mm | |||
| Alpa | 35 mm | still | Bayonet | 37.80 mm | |||
| Minolta Vectis | 30.2mm × 16.7mm APS | still | Bayonet | 38mm | |||
| Olympus E, Panasonic Lumix DMC-L, Leica Digilux | Four Thirds | 17.3mm x 12.98mm | digital still | ~44mmA[›] | Bayonet | 38.67 mm | |
| Aaton universal | 16 mm | movie | Breech lock | 40 mm | |||
| Konica A/R | 35 mm | still | Bayonet | 40.7 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 | 43.5 mm | |||
| Minolta SR/MC/MD | 35 mm | still | Bayonet | 43.5 mm | |||
| Petriflex | 35 mm | still | Breech lock | 43.5 mm | |||
| Canon EF | 35 mm | still | 54mm[1] | Bayonet | 44 mm | ||
| Canon EF-S | APS-C | digital still | 54mm[2] | Bayonet | 44 mm | ||
| Sigma SA | 35 mm | still | Bayonet | 44 mm | |||
| Paxette | 35 mm | still | M39 | 1 mm | Screw | 44 mm | |
| Praktica B | 35 mm | still | Bayonet | 44.4 mm | |||
| Minolta AF, Sony Alpha | 35 mm | still | Bayonet | 44.5 mm | |||
| Rolleiflex SL35 | 35 mm | still | Bayonet | 44.6 mm | |||
| Exakta, Topcon | 35 mm | still | Bayonet | 44.7 mm | |||
| Pentax K | 35 mm | still | Bayonet | 45.5 mm | |||
| Asahiflex | 35 mm | still | 37 mm | 1 mm | Screw | 45.5 mm | |
| Praktica | M42 lens mount | 35 mm | still | 42 mm | 1 mm | Screw | 45.5 mm |
| Yashica/Contax | 35 mm | still | Bayonet | 45.5 mm | |||
| Mamiya ZE | 35 mm | still | Bayonet | 45.5 mm | |||
| Olympus OM | 35 mm | still | Bayonet | 46 mm | |||
| Nikon F-mount | 35 mm | still | 44mm[3] | 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 | |||
| Tamron | T2, T-mount or T-thread | 35 mm | still | 42mm | 0.75 mm | Screw | 55 mm |
| Panavision PV mount | 35 mm | movie | Breech lock | 57.15 mm | |||
| Mamiya 7/7II | Medium format | still | Bayonet | ~60 mm ??? | |||
| Mitchell BNCR mount | 35 mm | movie | Breech lock | 61.468 mm | |||
| Mamiya 645 | Medium format | still | Bayonet | 63.3 mm | |||
| Leitz Visoflex II/III | 35 mm | still | Bayonet (Leica M) | 68.8 mm | |||
| Pentax 645 | Medium format | still | Bayonet | 70.87 mm | |||
| Arri Maxi PL | 70 mm | movie | 64mm | 73.5 mm | |||
| Pentacon Six | Medium format | still | Breech lock | 74.1 mm | |||
| Hasselblad | Medium format | still | Bayonet | 74.9 mm | |||
| Kowa Six/Super 66 | Medium format | still | breech lock | 79 mm | |||
| Pentax 6x7 | Medium format | still | Bayonet | 84.95 mm | |||
| Leitz Visoflex I | 35 mm | still | M39 | 26 TPI | Screw | 91.3 mm | |
| Bronica S2A | Medium format | still | 57 | 1 | Bayonet | 101.7 mm | |
| Rolleiflex SL66 | Medium format | still | Bayonet | 102.8 mm | |||
| Mamiya RZ | Medium format | still | Bayonet | 105 mm | |||
| Mamiya RB | Medium format | still | Bayonet | 112 mm |
Legend
| Column | Description |
|---|---|
| OEM model line(s) | primary manufacturer(s) or model line(s) with this mount |
| Interchangeable type name | interchangeable mounts used by multiple camera body and lens manufacturers |
| Frame size | maximum or typical film or image sensor format or size used for this mount |
| Camera type | digital, still, movie, CCTV, ... |
| Throat or thread diameter | Nominal inside-female or outside-male major diameter (D) with units: inch, mm, or M (ISO 68-1 metric thread pitch mm) |
| Mount thread pitch | (P) either: (Unified-thread) pitch count/inch, or (metric) mm/thread pitch |
| Mount type | Bayonet, Breech, Screw, ... |
| Flange focal distance | Nominal (mm) distance from film or image sensor to lens mount |
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".
Notes
^ A: The authoritative normative source for 4/3 standards information is Four-Thirds.Org and not 3rd-party reviews.
4/3's published facts:
- "Size of the 4/3-type Sensor: The standard diagonal length of the sensor is 21.63 millimetres (0.852 in). It is half that of 35-mm film format (36 millimetres (1.4 in) x 24 millimetres (0.94 in) = 43.27 millimetres (1.704 in)) and suitable format for professional use in digital age. The image circle of the interchangeable lens is specified based on this diagonal length. The focal length is about a half that of a 135 film camera lens assuming the same angle of view."[4]
- "The foundation for the high picture quality of the Four Thirds system is the lens mount, which is about twice the diameter of the image circle."[5]
- "Differences between Four Thirds System mount and Micro Four Thirds System mount: Mount diameter reduction; As a result of research aimed at facilitating the design of compact, lightweight lenses while maintaining the current strength, the outer diameter of the lens mount has been reduced by approx. 6 millimetres (0.24 in). ... the Micro Four Thirds System ... specifies the optimum flange back length required to reduce camera size and thickness, assuming the omission of the mirror box. The flange back length has been reduced to about 1/2 that of the Four Thirds System."[6]
So:
- 21.63mm * 2 = 43.26 millimetres (1.703 in) or ~44mm
- 43.26mm - 6mm = 37.26 millimetres (1.467 in) or ~38mm
- (21.63mm)^2 = ( ( 17.3mm ^ 2 ) + ( 12.98mm ^ 2 ) ); See: Pythagorean theorem (5^2 = 4^2 + 3^2)
NOTE: Some published reviews of 4/3 instead cite the (female) "outside diameter" of the lens or mount as ~50mm (and micro-4/3 as ~44mm),[7], and not the appropriate major diameter (D) ~44mm which is the camera body's female mount inside-diameter and the lens's male mount outside-diameter (micro-4/3 ~38mm).
References
- ^ "Camera Story - 1987-1991 EOS" (HTML). Canon. http://www.canon.com/camera-museum/history/canon_story/1987_1991/1987_1991.html. Retrieved 2008-07-22.
- ^ Canon EF-S lens mount has a 54 mm diameter throat
- ^ Nikon F-mount has a 44 mm diameter throat
- ^ "About Four Thirds, Standard, Whitepaper (Summary of Standard)" (HTML). Four Thirds System. http://www.four-thirds.org/en/about/standard.html. Retrieved 2008-08-11.
- ^ "About Four Thirds, Standard, Benefits of Four Thirds" (HTML). Four Thirds System. http://www.four-thirds.org/en/about/benefit.html. Retrieved 2008-08-11.
- ^ "Micro Four Thirds, Standard, Whitepaper (Summary of Standard)" (HTML). Four Thirds System. http://www.four-thirds.org/en/microft/whitepaper.html. Retrieved 2008-08-11.
- ^ "Olympus and Panasonic announce Micro Four Thirds" (HTML). Digital Photography Review. http://www.dpreview.com/news/0808/08080501microfourthirds.asp.
General references
- Markerink, Willem-Jan. "Camera mounts & registers". http://www.a1.nl/phomepag/markerink/mounts.htm.
See also
External links
- SLR Mount Identification Guide
- Standard: GOST 10332-72 (in Russian) — M42×1/45.5, M39×1/28.8
- Standard: GOST 10332-63 (in Russian) — M39×1/45.2 (aka «Z39»), M39×1/28.8, bayonet «C» (cameras: «Zenit-5», «Zenit-6», «Zenit-7»), bayonet «Zenit-7»
- Camera mounts & registers from Robert Monahan Medium Format Photography Megasite http://medfmt.8k.com/
- Camera mounts & registers from Willem-Jan Markerink http://www.markerink.org/WJM/HTML/mounts.htm
- Camera Mounts Sorted by Register
- Alphabetical List of Camera Mounts
- Nikon Lens Nomenclature - a study in frustration
- Adaptall-2.com
- Mechanical & Optical Instruments
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
