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 body allows interchangeable lenses, most usually the rangefinder camera, single lens reflex type, single lens mirrorless camera, 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.
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.
Bayonet mounts generally have a number of tabs (usually three or four) 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, either clockwise or counterclockwise, depending on the mount. It is then locked in place by a spring-loaded pin, which can be operated to remove the lens by rotating it in the opposite direction.
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, along with differing throat sizes. Many allege that these incompatibilities are due to the desire of manufacturers to "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 PL-mount 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.
List of lens mounts
Mount nameFlange focal distanceFrame size Throat or thread diameter Mount thread pitchMount typePrimary useCamera linesKinor 16SP mm16 mm mmBreech lockCinematographyKinor 16SP, Krasnogorsk-1, -2, -3 16mm movie camerasKinor 16SX mm16 mm mmBreech lockCinematographyKinor 16SX-1M,-2M 16mm movie cameraOST/OCT-19 mm35 mm mmBreech lockCinematographyKonvas-2M, Kinor-35H 35mm movie camerasKiev-16U mm16 mm mm mmScrewCinematographyKiev-16U/UE 16mm movie camerasKiev-16C mm16 mm mmmmScrewKiev-1C 16mm movie cameraCanon SV mmBayonetPhotography (Digital)Canon RC-701 & 760Argus C3 mm35 mm mm20 TPIScrewPhotographyArgus C3Canon EX mm1/2"BayonetPhotographyCanon FL mm35 mm mmBreech lockPhotographyCanon FD mm35 mm mmBreech lockPhotographyCanon F series, A series, and T series SLRsCanon FDn (a.k.a. "New FD") mm35 mm mmBayonetPhotographycompletely interchangeable with earlier FD lensesCanon EF mm35 mm mmBayonetPhotographyCanon EOS 35mm film SLR, Full Frame & APS-H DSLRCanon EF-S mmAPS-C mmBayonetPhotography (Digital)Canon EOS APS-C DSLRCanon EF-M mmAPS-C mm BayonetPhotography (Digital)Canon EOS M series Mirrorless APS-C CamerasCanon RF mm35 mm and APS-C mmBayonetPhotography (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 bodiesNikon S mm35 mm mmBayonetPhotographyNikon RangefinderNikon F mm35 mm mmBayonetPhotographyNikon F 35mm film SLR, Full Frame & APS-C DSLRNikon 1 mm13.2 x 8.8mm mmBayonetPhotography (Digital)Nikon 1 seriesNikon Z mm35 mm mmBayonetPhotography (Digital)Nikon Z - Mirrorless Full Frame, APS-C, & videoSony Mavica mmBayonetPhotography (Digital)Sony E FE mm35 mm and APS-C mm (1.815 inch)BayonetPhotography (Digital)Sony NEX Mirrorless APS-CMinolta SR mm35 mm mmBayonet (54°)PhotographyMinolta SR/MC/MDMinolta V mmAPS-H mmBayonetPhotographyMinolta VectisMinolta A mm35 mm and APS-C mm (1.939 inch)Bayonet (54°)PhotographyMinolta DSLR AF/Alpha/Dynax/MaxxumSony DSLR Alpha (α) A MountPentax Auto 110 mm110 film mmBayonetPhotographyPentax Auto 110 and Auto 110 SuperPentax Q mm1/2.3", 1/1.7" mmBayonetPhotography (Digital)Pentax K mm35 mm and APS-C mmBayonetPhotographyUsed also by Ricoh, Chinon, Agfa, Vivitar and KMZ Zenit camerasLeitz Visoflex I mm35 mmM3926 TPIScrewPhotographyLeitz Visoflex II/III mm35 mm mmBayonet (Leica M)PhotographyLeica M mm35 mm mmBayonetPhotographyLeica M seriesLeica CLMinolta CLELeica R mm35 mm mmBayonetPhotographyLeica L mm35 mm and APS-C mmBayonetPhotography (Digital)L-Mount Alliance (Leica, Panasonic, Sigma, DJI and Blackmagic Design cameras)Contax RF mm 35 mm44 mmDouble bayonetPhotographyContax I, II, III, IIa, IIIaKiev rangefindersContax G mm35 mm mmBreech lockPhotographyContax N mm35 mm mmBayonetPhotographyContax/Yashica mm35 mm mmBayonetPhotographyYashica/ContaxYashica MA~45.8 mm35 mmBayonetPhotographyKyocera Yashica 230 AF etc.Fujica X mm35 mm mmBayonetPhotographyFujica-XFujifilm X mmAPS-C mm BayonetPhotography (Digital)Fujifilm X series mirrorlessOlympus Pen F mm35 mm half-frameBayonetPhotographyOlympus OM mm35 mm mmBayonetPhotographyFour Thirds mm17.3 mm × 12.98 mm~44 mmBayonetPhotography (Digital)Olympus EPanasonic Lumix DMC-LLeica DigiluxMicro Four Thirds mm17.3 mm × 12.98 mm~38 mmBayonetPhotography (Digital)Olympus Pen & OM-D seriesPanasonic G, GF, GX & GH SeriesBlackmagic Design Cinema CameraKM mm (27.80 mm?)35 mm mmBayonetPhotographyKonica Hexar RFKonica F mm35 mm mmBayonetPhotographyKonica FKonica AR mm35 mm mmBayonetPhotographyKonica AutoreflexSamsung NX mini mm1" mmBayonetphotography (Digital)Samsung NX mmAPS-C mmBayonetPhotography (Digital)Samsung Kenox mm35 mmBayonetPhotographyManual focus only; there is only one compatible camera - Samsung Kenox GX-1/Samsung SR4000.DJI DL mm35 mm and APS-C mmBayonetPhotography (Digital), CinematographyFor aerial drone and gimbal use; DJI Zenmuse X7, X9 and DJI Ronin 4D X9 cameras.Icarex BM mm35 mmBreech lockPhotographyIcarex 35SD mm8 mm mm (0.625 inch)32 TPIScrewCinematographyCS6 mm1/3", 1/2" mm (1 inch)32 TPIScrewCinematography / IndustrialC mm (0.69 inches)1/2", 16 mm, 2/3", 1" mm (1 inch)32 TPIScrewCinematography / Industrial / Machine VisionS (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 pitchScrewCCTV, PCBEdmund Optics μ-VideoBolex Bajonet mm16 mmBreech lockCinematographyeffective focal distance mm (0.69 inches) due to beam splitter behind mount flange (accepts C-mount lenses with adapter)1/3" bayonet mount mm1/3" (x2.94)BayonetVideoJVC professional video camerasM39 (a.k.a. L-Mount, LTM) mm35 mmM3926 TPIScrewPhotographyLeica M39 screw mountNarciss mm16 mmM241 mmScrewPhotography1/2" bayonet mount mm1/2" (x3.92)BayonetVideoNon-Sony professional video camerasAlpa mm35 mm mmBayonetPhotographySony 1/2" Video mm1/2" (x3.92)BayonetVideoSony professional video camerasAaton universal mm16 mm mmBreech lockCinematographyMiranda bayonet/M44 mm35 mm and APS-CBayonetPhotographyMiranda Camera CompanyPetriflex mm35 mmBreech lockPhotographySigma SA mm35 mm mmBayonetPhotographySigma SAPaxette mm35 mmM391 mmScrewPhotographyPraktiflex mm35 mmM401 mmScrewPhotographyPraktica mm35 mm mmBayonetPhotographyExakta mm35 mm mmBayonetPhotographyExakta, Topcon SuperZenit M39 mm35 mmM391 mmScrewPhotographyM37 mm35 mm mm1 mmScrewPhotographyAsahiflexM42 mm35 mm mm1 mmScrewPhotographyPraktica,The M42 (Praktica) mount is sometimes referred to as a "P" thread. See, e.g., Pentax, ZenitB4-mount mm2/3" (x5.4)Breech lockVideoProfessional and broadcast video camerasPraktina mm35 mm mmBreech lockPhotographyT-Thread (Very earliest type) mm35 mmM370.75mmScrewPhotographyTamronAdapt-A-Matic mm35 mm mmBayonetPhotographyTamronAdaptall & Adaptall-2 mm35 mm mmBayonetPhotographyTamronArri standard mm35 mm and 16 mm mmTab lockCinematographyArri bayonet mm35 mm and 16 mm mmBayonetCinematographyArri PL mm35 mm and 16 mm mmBreech lockCinematographyArri LPL mmArri LF mmBreech lockCinematographyArri Maxi PL mm70 mm mmCinematographyT mm35 mm mm0.75 mmScrewPhotographyTamronYS Auto T-Thread mm35 mm mm0.75 mmScrewPhotographySigma CorporationT-thread mm35 mm mm0.75 mmScrewPhotographyTokinaH-Mount mm35 mm mm0.75 mmScrewPhotographyHanimex (rebranding of Tokina M47)Panavision PV mm35 mm mmBreech lockCinematographyB3-mount mm2/3"Reverse bayonetVideoIkegamiMitchell BNCR mm35 mm mmBreech lockCinematographyZeiss Panflex 5522/23 for Contax RF mm 35 mmDouble bayonetPhotographyKowa Six/Super 66 mm6×6Breech lockPhotographyHasselblad mm6×6 mmBayonetPhotographyHasselblad Xpan mm35 mm panoramic mmBayonetPhotographyBronica ETR mm6×4.5BayonetPhotographyBronica RF mm6×4.5BayonetPhotographyBronica SQA mm6×6 mmBayonetPhotographyBronica GS1 mm6×7 mmBayonetPhotographyMamiya 645 mm6×4.5 mmBayonetPhotographyMamiya 6 mm (approx.)6×6BayonetPhotographyMamiya 7/7II mm (approx.)6×7 mmBayonetPhotographyMamiya RZ67 mm6×7 mmBayonetPhotographyMamiya RB67 mm6×7 mmBayonetPhotographyMamiya ZE mm35 mmBayonetPhotographyMamiya/Sekor E mm35 mm mmBayonetPhotographyPentax 645 mm6×4.5 mmBayonetPhotographyPentax 6x7 mm6×7 mmBayonetPhotographyPentacon Six mm6×6 mmBreech lockPhotographyFujifilm G mm43.8x32.9 mm mmBayonetPhotography (Digital)Fujifilm GFX seriesRolleiflex SL66 mm6×6BayonetPhotographyRolleiflex SL35 mm35 mm mmBayonetPhotographyRMS thread, society thread/180 mm0.8", Whitworth36 tpiScrewMicroscopeolder microscopesLeicaNikon BiologicalUnknownM250.75 mmScrewMicroscopeBD MountUnknownM260.7 mmScrewMicroscopeMitutoyoOlympus BDNikon BDZeissUnknownM270.75 mmScrewMicroscopeTFL mm28 mmM350.75 mmScrewMachine VisionTFL II mm35 mmM480.75 mmScrewMachine VisionPentax Auto 110 mm110 Film20.6 mmBayonetPhotographyAuto 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)
Focusing lens mount
The axial adjustment range for focusing Ultra wide angle lenses and some Wide-angle lenses in large format cameras 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.
Secondary lens mount