Lens mount

A lens mount is an interface – mechanical and often also electrical – between a photographic camera body and a lens. It is a feature of camera systems where the System camera, most usually the rangefinder camera, single lens reflex type, single lens mirrorless type or any movie camera of 16 mm or higher film 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.

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Mount types A lens mount may be a screw-threaded type, a bayonet-type, or a breech-lock (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.

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 inserted in only 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 (Sony, Nikon, Canon, Contax/Yashica, Pentax, etc.) are almost always incompatible. In addition to the mechanical and electrical interface variations, the flange focal distance from the lens mount to the film or sensor can also be different. Many allege that these incompatibilities are due to the desire of manufacturers to "vendor lock-in" consumers to their brand.

In movie cameras, the two most popular mounts in current usage on professional digital cinematography cameras are Arri's Arri PL and Panavision's PV mount. The PL-Mount is used both on Arri and RED digital cinematography cameras, which are the most used cameras for films shot in digital. 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.

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List of lens mounts

!Mount name !Flange focal distance !Frame size ! data-sort-type=text Throat or thread diameter ! data-sort-type=text	Mount thread pitch !Mount type !Primary use !Camera lines
Kinor 16SP	mm	16 mm	mm		Breech lock	Cinematography	Kinor, Krasnogorsk-1, -2, -3 16mm movie cameras
Kinor 16SX	mm	16 mm	mm		Breech lock	Cinematography	Kinor 16SX-1M,-2M 16mm movie camera
OST/OCT-19	mm	35 mm	mm		Breech lock	Cinematography	Konvas, Kinor-35H 35mm movie cameras
Kiev-16U	mm	16 mm	mm	mm	Screw	Cinematography	Kiev-16U/UE 16mm movie cameras
Kiev-16C	mm	16 mm	mm	mm	Screw		Kiev-1C 16mm movie camera
Canon SV	mm				Bayonet	Photography (Digital)	Canon RC-701 & 760
Argus C3	mm	35 mm	mm	20 TPI	Screw	Photography	Argus C3
Canon EX	mm	1/2"			Bayonet	Photography
Canon FL	mm	35 mm	mm		Breech lock	Photography
Canon FD	mm	35 mm	mm		Breech lock	Photography	Canon F series, A series, and T series SLRs
Canon FDn (a.k.a. "New FD")	mm	35 mm	mm		Bayonet	Photography	completely interchangeable with earlier FD lenses
Canon EF	mm	35 mm	mm		Bayonet	PhotographyCanon EOS 35mm film SLR, Full Frame & APS-H DSLR
Canon EF-S	mm	APS-C	mm		Bayonet	Photography (Digital)Canon EOS APS-C DSLR
Canon EF-M	mm	APS-C	mm		Bayonet	Photography (Digital)	Canon EOS M series Mirrorless APS-C Cameras
Canon RF	mm	35 mm and APS-C	mm		Bayonet	Photography (Digital)	Canon EOS R series full-frame and APS-C mirrorless cameras; lenses designated as RF-S are optimized for APS-C sensors, but will mount on full-frame bodies
Nikon S-mount	mm	35 mm	mm		Bayonet	Photography	Nikon S-mount
Nikon F-mount	mm	35 mm	mm		Bayonet	Photography	Nikon F-mount 35mm film SLR, Full Frame & APS-C DSLR
Nikon 1	mm	13.2 x 8.8mm	mm		Bayonet	Photography (Digital)	Nikon 1 series
Nikon Z-mount	mm	35 mm	mm		Bayonet	Photography (Digital)	Nikon Z - Mirrorless Full Frame, APS-C, & video
Sony Mavica	mm				Bayonet	Photography (Digital)
FE>Sony E-mount	mm	35 mm and APS-C	mm (1.815 inch)		Bayonet	Photography (Digital)	Sony NEX Mirrorless APS-C>Sony NEX
Minolta SR-mount	mm	35 mm	mm		Bayonet (54°)	Photography	Minolta SR/MC/MD
Minolta V	mm	APS-H	mm		Bayonet	Photography	Minolta Vectis
Minolta A-mount	mm	35 mm and APS-C	mm (1.939 inch)		Bayonet (54°)	Photography	Minolta DSLR AF/Alpha/Dynax/Maxxum Sony DSLR Alpha (α) A Mount
Pentax Auto 110	mm	110 film	mm		Bayonet	Photography	Pentax Auto 110 and Auto 110 Super
Pentax Q	mm	1/2.3", 1/1.7"	mm		Bayonet	Photography (Digital)
Pentax K	mm	35 mm and APS-C	mm		Bayonet	Photography	Used also by Ricoh, Chinon, Agfa, Vivitar and KMZ Zenit cameras
Leitz Visoflex I	mm	35 mm	M39	26 TPI	Screw	Photography
Leitz Visoflex II/III	mm	35 mm	mm		Bayonet (Leica M)	Photography
Leica M	mm	35 mm	mm		Bayonet	Photography	Leica M series Leica CL Minolta CLE
Leica R	mm	35 mm	mm		Bayonet	Photography
Leica L-Mount	mm	35 mm and APS-C	mm		Bayonet	Photography (Digital)	L-Mount Alliance (Leica, Panasonic, Sigma, DJI and Blackmagic Design cameras)
Contax RF	mm	35 mm	44 mm		Double bayonet	Photography	Contax I, II, III, IIa, IIIa Kiev rangefinders
Contax G	mm	35 mm	mm		Breech lock	Photography
Contax-N	mm	35 mm	mm		Bayonet	Photography
Contax/Yashica	mm	35 mm	mm		Bayonet	Photography	Yashica/Contax
Yashica MA	~45.8 mm	35 mm			Bayonet	Photography	Kyocera Yashica 230 AF etc.
Fujica X-mount	mm	35 mm	mm		Bayonet	Photography	Fujica-X
Fujifilm X-mount	mm	APS-C	mm		Bayonet	Photography (Digital)	Fujifilm X series mirrorless
Olympus Pen F	mm	35 mm half-frame			Bayonet	Photography
Olympus OM	mm	35 mm	mm		Bayonet	Photography
Four Thirds	mm	17.3 mm × 12.98 mm	~44 mm		Bayonet	Photography (Digital)	Olympus E Panasonic Lumix DMC-L Leica Digilux
Micro Four Thirds	mm	17.3 mm × 12.98 mm	~38 mm		Bayonet	Photography (Digital)	Olympus Pen & OM-D series Panasonic G, GF, GX & GH Series Blackmagic Design Cinema Camera
KM-mount	mm (27.80 mm?)	35 mm	mm		Bayonet	Photography	Konica Hexar RF
Konica F-mount	mm	35 mm	mm		Bayonet	Photography	Konica F
Konica AR-mount	mm	35 mm	mm		Bayonet	Photography	Konica Autoreflex
Samsung NX mini	mm	1"	mm		Bayonet	photography (Digital)
Samsung NX-mount	mm	APS-C	mm		Bayonet	Photography (Digital)
Samsung GX-mount	mm	35 mm			Bayonet	Photography	Manual focus only; there is only one compatible camera - Samsung Kenox GX-1/Samsung SR4000.
DL-mount	mm	35 mm and APS-C	mm		Bayonet	Photography (Digital), Cinematography	For aerial drone and gimbal use; DJI Zenmuse X7, X9 and DJI Ronin 4D X9 cameras.
Icarex BM	mm	35 mm			Breech lock	Photography	Icarex 35S
D mount	mm	8 mm	mm (0.625 inch)	32 TPI	Screw	Cinematography
CS	6 mm Alexander Hornberg (2007). 9783527610143, John Wiley & Sons. . ISBN 9783527610143	1/3", 1/2"	mm (1 inch)	32 TPI	Screw	Cinematography / Industrial
C-mount	mm (0.69 inches)	1/2", 16 mm, 2/3", 1"	mm (1 inch)	32 TPI	Screw	Cinematography / Industrial / Machine Vision
S (a.k.a. M12)	N/A. Screw mount must be adjusted manually for back focus. Back focal distance from <1mm to 12mm.	1/6" to 1"	12 mm	0.5 mm pitch	Screw	CCTV, PCB	Edmund Optics μ-Video
Bolex Bajonet	mm	16 mm			Breech lock	Cinematography	effective focal distance mm (0.69 inches) due to beam splitter behind mount flange (accepts C-mount lenses with adapter)
1/3" bayonet mount	mm	1/3" (x2.94)			Bayonet	Video	JVC professional video cameras
M39 (a.k.a. L-Mount, LTM)	mm	35 mm	M39	26 TPI	Screw	Photography	Leica M39 screw mount
Narciss	mm	16 mm	M24	1 mm	Screw	Photography
1/2" bayonet mount	mm	1/2" (x3.92)			Bayonet	Video	Non-Sony professional video cameras
Alpa	mm	35 mm	mm		Bayonet	Photography
Sony 1/2" Video	mm	1/2" (x3.92)			Bayonet	Video	Sony professional video cameras
Aaton universal	mm	16 mm	mm		Breech lock	Cinematography
Miranda bayonet/M44	mm	35 mm and APS-C			Bayonet	Photography	Miranda Camera Company
Petriflex	mm	35 mm			Breech lock	Photography
Sigma SA	mm	35 mm	mm		Bayonet	Photography	Sigma SA
Paxette	mm	35 mm	M39	1 mm	Screw	Photography
Praktiflex	mm	35 mm	M40	1 mm	Screw	Photography
Praktica	mm	35 mm	mm		Bayonet	Photography
Exakta	mm	35 mm	mm		Bayonet	Photography	Exakta, Topcon Super
Zenit M39	mm	35 mm	M39	1 mm	Screw	Photography
M37	mm	35 mm	mm	1 mm	Screw	Photography	Asahiflex
M42	mm	35 mm	mm	1 mm	Screw	Photography	Praktica,The M42 (Praktica) mount is sometimes referred to as a "P" thread. See, e.g., Pentax, Zenit
B4-mount	mm	2/3" (x5.4)			Bayonet	Video	Professional and broadcast video cameras
Praktina	mm	35 mm	mm		Breech lock	Photography
T-Thread (Very earliest type)	mm	35 mm	M37	0.75mm	Screw	Photography	Tamron
Adapt-A-Matic	mm	35 mm	mm		Bayonet	Photography	Tamron
Adaptall & Adaptall-2	mm	35 mm	mm		Bayonet	Photography	Tamron
Arri standard	mm	35 mm and 16 mm	mm		Tab lock	Cinematography
Arri bayonet	mm	35 mm and 16 mm	mm		Bayonet	Cinematography
Arri PL	mm	35 mm and 16 mm	mm		Breech lock	Cinematography
Arri LPL	mm	Arri LF	mm		Breech lock	Cinematography
Arri Maxi PL	mm	70 mm	mm			Cinematography
T-mount	mm	35 mm	mm	0.75 mm	Screw	Photography	Tamron
YS Auto T-Thread	mm	35 mm	mm	0.75 mm	Screw	Photography	Sigma Corporation
T-thread	mm	35 mm	mm	0.75 mm	Screw	Photography	Tokina
H-Mount	mm	35 mm	mm	0.75 mm	Screw	Photography	Hanimex (rebranding of Tokina M47)
PV mount	mm	35 mm	mm		Breech lock	Cinematography
B3-mount	mm	2/3"			Reverse bayonet	Video	Ikegami
BNCR mount	mm	35 mm	mm		Breech lock	Cinematography
Zeiss Panflex 5522/23 for Contax RF	mm	35 mm			Double bayonet	Photography
Kowa Six/Super 66	mm	6×6			Breech lock	Photography
Hasselblad	mm	6×6	mm		Bayonet	Photography
Hasselblad Xpan	mm	35 mm panoramic	mm		Bayonet	Photography
Bronica ETR	mm	6×4.5			Bayonet	Photography
Bronica RF		6×4.5			Bayonet	Photography
Bronica SQA	mm	6×6	mm		Bayonet	Photography
Bronica GS1	mm	6×7	mm		Bayonet	Photography
Mamiya 645	mm	6×4.5	mm		Bayonet	Photography
Mamiya 6	mm (approx.)	6×6			Bayonet	Photography
Mamiya 7/7II	mm (approx.)	6×7	mm		Bayonet	Photography
Mamiya RZ67	mm	6×7	mm		Bayonet	Photography
Mamiya RB67	mm	6×7	mm		Bayonet	Photography
Mamiya ZE	mm	35 mm			Bayonet	Photography
Mamiya/Sekor E	mm	35 mm	mm		Bayonet	Photography
Pentax 645	mm	6×4.5	mm		Bayonet	Photography
Pentax 6x7	mm	6×7	mm		Bayonet	Photography
Pentacon Six	mm	6×6	mm		Breech lock	Photography
Fujifilm G-mount	mm	43.8x32.9 mm	mm		Bayonet	Photography (Digital)	Fujifilm GFX series
Rolleiflex SL66	mm	6×6			Bayonet	Photography
Rolleiflex SL35	mm	35 mm	mm		Bayonet	Photography
RMS thread, society thread	/180 mm		0.8", Whitworth	36 tpi	Screw	Microscope	older microscopes
Leica Nikon Biological	Unknown		M25	0.75 mm	Screw	Microscope
BD Mount	Unknown		M26	0.7 mm	Screw	Microscope	Mitutoyo Olympus BD Nikon BD
Zeiss	Unknown		M27	0.75 mm	Screw	Microscope
TFL-mount	mm	28 mm	M35	0.75 mm	Screw	Machine Vision
TFL II	mm	35 mm	M48	0.75 mm	Screw	Machine Vision
Pentax Auto 110	27 mm	110 Film	20.6 mm		Bayonet	Photography	Auto 110

For small camera modules, used in e.g. CCTV systems and machine vision, a range of metric thread mounts exists. The smallest ones can be found also in e.g. cellphones and endoscopes. The most common by far is the M12x0.5, followed by M8x0.5 and M10x0.5.

• M4.2x0.2 (1/7" sensors)
• M4.6x0.25 (1/5", 2.4mm, 3.8mm sensors, industrial endoscopes)
• M5x0.35 (1/6", 1/5" sensors)
• M5.5x0.35 (1.7", 1/5.8", 1/5", 1/4" sensors)
• M6x0.35 (1/4", 5.2mm, 4.85mm sensors)
• M6.4x0.25 (1/3" sensors)
• M7x0.35 (1.8", 1.7", 1/6", 1/5", 1/4", 1/3.6", 1/3.2", 1/2.7", 4.85mm sensors)
• M8x0.35 (1/4", 1/3" sensors)
• M8x0.5 (1/5", 1/4", 1/3" sensors; sometimes occurs in diode laser modules)
• M9x0.5 (1/2.7", 1/3", 1/3.2" sensors; also commonly encountered in diode laser modules)
• M10x0.5 (1/4", 1/3" sensors)
• M12x0.5 (the S-mount, listed in the table)
• M22x0.5 (1/1.2" sensors)

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Focusing lens mount The axial adjustment range for focusing Ultra wide angle lenses and some in View camera is usually very small.

So some manufacturers (e.g. Linhof) offered special focusing lens mounts, so-called wide-angle focusing accessories for their cameras. With such a device, the lens could be focused precisely without moving the entire front standard.

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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 and secondary lenses like , which mount in between the camera body and the primary lens, both using and providing a primary lens mount. Various lensmakers also offer optical accessories that mount in front of the lens; these may include wide-angle lens, telephoto, fisheye lens, and close-up or macro adapters.

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 provide 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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Lens mount adapters Lens mount adapters are designed to attach a lens to a camera body with non-matching mounts. Generally, a lens can be easily adapted to a camera body with a smaller flange focal distance by simply adding space between the camera and the lens. When attempting to adapt a lens to a camera body with a larger flange focal distance, the adapter must include a secondary lens in order to compensate. This has the side effect of decreasing the amount of light that reaches the sensor, as well as adding a crop factor to the lens. Without the secondary lens, these adapters will function as an extension tube and will not be able to focus to infinity.

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See also

• ISO metric screw thread
• Lens board

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Notes 4/3's published facts:

• "Size of the 4/3-type Sensor: The standard diagonal length of the sensor is . It is half that of 35-mm film format ( x = ) 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."
• "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."
• "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. . ... 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."

So:

• 21.63mm * 2 = or ~44mm
• 43.26mm – 6mm = or ~38mm
• $\backslash mathrm\{(21.63\backslash \; mm)^2\; =\; 17.3\backslash \; mm\; ^\; 2\; +\; 12.98\backslash \; mm\; ^\; 2\}$; 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), 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).

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Sources

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External links

• SLR Mount Identification Guide
• List of Camera, Mount Type and Register for Mechanical & Optical Instruments
• /a>, Camera mounts & registers from Robert Monahan Medium Format Photography Megasite
• http://www.markerink.org/WJM/HTML/mounts.htm, Camera mounts & registers from Willem-Jan Markerink
• Camera Mounts Sorted by Register
• Alphabetical List of Camera Mounts
• Nikon Lens Nomenclature – a study in frustration
• Adaptall-2.com
• DPReview Hands-on preview of Fujifilm X-Pro1
• DPreview Hands-on preview of Canon EOS M
• 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» (in Russian)

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