![]() | This article includes a list of general references, but it lacks sufficient corresponding inline citations .(March 2013) |
For an interchangeable lens camera, the flange focal distance (FFD) (also known as the flange-to-film distance, flange focal depth, flange back distance (FBD), flange focal length (FFL), back focus [1] or register, depending on the usage and source) of a lens mount system is the distance from the mounting flange (the interlocking metal rings on the camera and the rear of the lens) to the film or image sensor plane. This value is different for different camera systems. The range of this distance, which will render an image clearly in focus within all focal lengths, is usually measured to a precision of hundredths of millimetres, and is not to be confused with depth of field.
Lenses can be adapted from one mount (and respective FFD) to another. FFD determines whether infinity focus can be accomplished with a simple non-optical adapter. Optics to correct for distance introduce more cost and can lower image quality, so non-optical lens adapters are preferred. A simple non-optical adapter holds the longer FFD lens the appropriate additional distance away from the sensor or film on the shorter FFD camera. A camera body with a shorter FFD can accept a larger number of lenses (those with a longer FFD) by using a simple adapter. A lens with a longer FFD can be more readily adapted to a larger number of camera bodies (those with a shorter FFD). If the difference is small, other factors such as the sizes and positions of the mounting flanges will influence whether a lens can be adapted without optics.
Typically, camera bodies with shorter flange focal distance can be adapted more readily to lenses with longer flange focal distance.
Mount | Flange focal distance | Type | Format | Production | Prime lenses | Zoom lenses | Wide/tele converters | Mount converters | Comments |
---|---|---|---|---|---|---|---|---|---|
Samsung NX mini | 6.95 mm | Mirrorless | 1" | 2014–2015 | 2 | 1 | |||
Pentax Q-mount | 9.2 mm [2] | Mirrorless | 1/2.3" (6.17×4.55 mm) / 1/1.7" | 2011–2019 | 5 | 3 | 0 | 1 | |
M58×0.75 mm mount | 12 mm | Industrial | 24×36 mm | Industrial area and line scan cameras | |||||
D-mount | 12.29 mm | cine | 8 mm | (8 mm movie cameras) | |||||
CS-mount | 12.526 mm [3] [4] [5] | TV | 1/4", 1/3", 1/2" | (surveillance cameras) | |||||
Nikon Z-mount | 16 mm | Mirrorless | 24×36 mm | 2018– | 19 | 11 | 1 | ||
APS-C (DX) | 2018– | 1 | 4 | 2 | Can use any of the 24x36 mm lenses and the FTZ/FTZ II mount adaptor. | ||||
DJI DL-mount | 16.84 [6] | Mirrorless | Super 35 | 2017– | 4 | 0 | |||
Nikon 1-mount | 17.00 mm [7] | Mirrorless | CX | 2011–2018 | 3 | 8 | 1 | ||
C-mount | 17.526 mm [8] [9] | cine / TV | 8 mm, 16 mm, 1/3", 1/2", 2/3", 1", 4/3" | ~1926– | (Bolex, Eclair and Bell & Howell) | ||||
Fujifilm X-mount | 17.7 mm | Mirrorless | APS-C | 2012– | 23 | 14 | 2 | 1 [10] | |
Canon EF-M-mount | 18.00 mm | Mirrorless | APS-C | 2012– | 3 | 5 | 0 | 1 | |
Sony E-mount | 18.00 mm | Mirrorless | APS-C | 2010– | 6 | 14 | 4 | 2 | Lens count doesn't include 3rd party products. All FE lenses (see below) can also be used on APS-C E-mount cameras. |
24×36 mm (FE) | 2013– | 22 | 17 | 4 | 3 | Lens count doesn't include 3rd party products. | |||
Sony FZ-mount | 19.00 mm | cine | Super 35 | 2011– | 0 | 2 | 0 | 3 | |
24×36 mm | 2015– | 1 | 2 | ||||||
Micro Four Thirds System | 19.25 mm | Mirrorless | 4/3" | 2008– | 37 | 28 | 1 | 1 | |
Hasselblad XCD mount | 18.14 mm (+0.05/-0.00) | Mirrorless | Medium Format (127) 43.8×32.9 mm | 2017– | 13 | 1 | 3 | for Hasselblad X System | |
Canon RF mount | 20.00 mm | Mirrorless | 24×36 mm | 2018– | 12 | 11 | 3 | ||
Leica L-Mount (formerly CL-mount) | 20.00 mm | Mirrorless | 24×36 mm, APS-C | 2014– | 19 | 12 | |||
JVC 1/3" bayonet mount | 25.00 mm | TV | 1/3" 3-CCD (5.24×2.94 mm) | ||||||
Samsung NX-mount | 25.50 mm | Mirrorless | APS-C | 2010–2015 | 8 | 8 | |||
Fujifilm G-mount | 26.7 mm | Mirrorless | Medium Format (127) 43.8×32.9 mm | 2017– | 7 | 2 | 1 | for Fujifilm GFX series cameras | |
Pentax Auto 110 | 27.00 mm | SLR | 13×17 mm | 1978–1985 | 5 | 1 | 0 | 0 | |
RED ONE interchangeable mount | 27.30 mm | cine | |||||||
Leica M-mount | 27.8 (inner rails) <-> 27.95 (outer rails) mm [10] | Mirrorless | 24×36 mm | 1954– | aka Voigtländer VM-mount, Epson EM-mount, Zeiss ZM-mount as well as Konica KM-mount (Hexar RF) and Minolta M-mount (CL/CLE) | ||||
Nikonos | 28.00 mm [11] | underwater | 24x36 mm | 1963-2001 | 6 | 0 | 0 | 0 | this is the underwater scale focusing camera |
M39×26tpi mount | 28.80 mm | Mirrorless | 24×36 mm | Leica M39×26tpi aka LTM (Leica Thread Mount) aka L39 (not to be confused with M39×1) | |||||
M39×1/28.8 mount | 28.80 mm [12] | Mirrorless | 24×36 mm | 1948-1978 | Zorki M39×1/28.8 for Zorki cameras (not to be confused with M39×1 and M39x26tpi) | ||||
Contax G-mount | 29.00 mm | Mirrorless | 24×36 mm | 1994–2005 | 6 | 1 | 0 | 1 | |
Olympus PEN F (film) | 28.95 mm | SLR | 18×24 mm | 1963–1972 | 16 | 2 | |||
Hasselblad XPan | 34.27 mm | Mirrorless | 24×36 mm & 24×65 mm | 1998–2003 | 3 | 0 | 0 | 0 | Identical to Fujifilm TX series cameras and mount |
Contax RF-mount | 34.85 mm | Mirrorless | 24×36 mm | ||||||
Nikon S-mount | 34.85 mm | Mirrorless | 24×36 mm | 1947–2005 | |||||
1/2" TV bayonet mount | 35.74 mm | TV | 1/2" 3-CCD | JVC, Hitachi, Panasonic, others, but not Sony | |||||
Minolta V-mount | 36.00 mm | SLR | APS-H | 1996–1999 | 3 | 5 | 0 | 1 | Vectis S-1, Vectis S-100, Dimâge RD 3000 |
Sony 1/2" TV bayonet mount | 38.00 mm | TV | 1/2" 3-CCD | ||||||
Olympus Four Thirds System | 38.67 mm | SLR | 4/3" | 2003–2017 | 12 | 30 | 2 | ||
Aaton mount | 40.00 mm | cine | 16 mm/S16 | ||||||
Panavision SP70-mount | 38.00 mm | cine | 2018– | 35 mm & 65 mm | |||||
Konica F-mount | 40.50 mm | SLR | 24×36 mm | 1960–1965 | 17 | 0 | 0 | 0 | |
Konica AR-mount | 40.50 mm | SLR | 24×36 mm | 1965–1988 | 36 | 16 | 1 | 0 | |
Canon FL-mount | 42.00 mm | SLR | 24×36 mm | 1964–1971 | |||||
Canon FD-mount | 42.00 mm | SLR | 24×36 mm | 1971–1990 | 107 | 34 | |||
Start (Soviet SLR) | 42.00 mm | SLR | 1958–1964 | ||||||
Minolta SR-mount | 43.50 mm | SLR | 24×36 mm | 1958–2001 | 6 | ||||
Fujica X-mount | 43.50 mm | SLR | 24×36 mm | 1980–1985 | |||||
Pentaflex (16 mm cameras) | 44.00 mm | cine | |||||||
Canon EF-mount | 44.00 mm | SLR | 24×36 mm / APS-H / APS-C | 1987– | 47 | 64 | |||
Canon EF-S-mount | 44.00 mm | SLR | APS-C | 2003– | 2 | 9 | 0 | 0 | |
Praktica B-mount | 44.40 mm | SLR | 24×36 mm | 1978–1990 | |||||
Sigma SA-mount | 44.00 mm | SLR | 24×36 mm / APS-C | 1992– | 14 | 19 | 2 | 4 | |
Arri LPL | 44.00 mm | cine | 25.54x36.70 mm | 2018- | for Arri Alexa LF | ||||
Minolta/Konica Minolta/Sony A-mount | 44.50 mm | SLR | 24×36 mm | 1985– | 42+0+17 | 50+2+13 | 6+0+2 | 2+0+0 | |
APS-C | 2004– | 0+0+3 | 0+3+13 | 0+0+0 | 0+0+0 | ||||
Rollei QBM | 44.50 mm [13] | SLR | 24×36 mm | 1970– | Rollei, Voigtländer | ||||
Samsung Kenox mount | 44.50 mm | SLR | 24×36 mm | 1997–2002 | 1 | 2 (3?) | 0 | 0 | Although designed in 1990s, mount is manual-focus only; lenses mount and lock on a slightly modified Minolta A-mount adapters |
Exakta | 44.7 mm [14] | SLR | 24×36 mm | 1936–1969 | |||||
M39x1 | 45.20 mm [15] | SLR | 24×36 mm | 1952–1968 | Early Russian SLRs (Zenit) (not to be confused with M39×26tpi and M39×1/28,8) | ||||
M37×1 | 45.46 mm | SLR | 24×36 mm | 1952-1957 | Asahiflex I, Asahiflex IA (Tower 23), Asahiflex IIB (Tower 23/24), Asahiflex IIA (Tower 22) | ||||
M42×1 | 45.46 mm | SLR | 24×36 mm | 1949– | Pentacon, Pentax, Contax S, Praktica, Zeiss ZS, Zenit, many others (not to be confused with T-mount, which is M42×0.75) | ||||
Pentax K-mount | 45.46 mm | SLR / Mirrorless | 24×36 mm / APS-C | 1975– | 147 [16] | 108 | 8 | 3 | Used also by some Samsung, Ricoh, Chinon, Agfa, Vivitar, Petri and KMZ (Zenit) cameras. Lens count only for Pentax-branded lenses. |
Contax C/Y-mount | 45.50 mm | SLR | 24×36 mm | 1974–2005 | 24 | 5 | 3 | Used by some Contax and Yashica SLR cameras | |
Petri Bayonet | 45.50 mm | SLR | 24×36 mm | Petri SLRs 1960-77. | |||||
Mamiya Z | 45.50 mm | SLR | 24×36 mm | 1980– | |||||
Kodak Retina DKL-mount | 45.7 mm | SLR / Mirrorless | 24×36 mm / 28×28 mm | 1958–1977 | 12+6 | 0 | 0 | 0 | DKL variants used by Retina Reflex S (034), Retina Reflex III (041), Retina Reflex IV (051, 051/N), Instamatic Reflex (062), Retina IIIS |
Voigtländer Bessamatic DKL-mount | 45.7 mm | SLR | 24×36 mm | 1958–1967 | 11+2 | 1 | 0 | 0 | DKL variants used by Bessamatic, Bessamatic deLuxe, Bessamatic m, Bessamatic CS, Ultramatic, Ultramatic CS |
Braun Paxette Reflex DKL-mount | 45.7 mm | SLR / Mirrorless | 24×36 mm | DKL variant used by Paxette Reflex Automatic, Paxette Reflex Automatic II, Tower 33 Reflex, Tower 34 Reflex; Balda Baldamatic III; Witt Iloca Electric / Graflex Graphic 35 Electric; Wirgin Edixa Electronica / Revue Edixa Electronica | |||||
Voigtländer Vitessa T DKL-mount | 45.7 mm | Mirrorless | 24×36 mm | 4+? | 0 | 0 | 0 | DKL variant used by Voigtländer Vitessa T; Braun Colorette (Super) II, Colorette (Super) IIB, Colorette (Super) IIL, Colorette (Super) IIBL; Wittnauer Continental, Wittnauer Professional | |
Yashica MA-mount | 45.80 mm | SLR | 24×36 mm | 1 | (measured); 230AF etc. | ||||
Olympus OM-mount | 46.00 mm | SLR | 24×36 mm | 1972–2002 | 38 | 14 | |||
Nikon F-mount | 46.50 mm | SLR | 24×36 mm / APS-C | 1959– | 213 | 117 | Used by some Kiev F-mount cameras. Only Nikon manufactured lenses counted. Nikon claims that there is over 400 Nikkor lens models manufactured. [17] | ||
Leica R-mount | 47.00 mm | SLR | 24×36 mm | 1964–2009 | |||||
KMZ Zenit DKL-mount | 47.58 mm | SLR | 24×36 mm | 1964–1968 | 5 | 1 | 0 | 0 | Zenit/Зенит 4/5/6 "Байонет Ц", an unofficial DKL-mount variant |
B4-mount | 48.00 mm | TV | 2/3" 3-CCD (9.6×5.4 mm) | 1992– | Mount was in use since at least 1978, wasn't officially standardized until 1992. | ||||
Contax N | 48.00 mm | SLR | 24×36 mm | 2000–2005 | 4 | 5 | 0 | 1 | |
Tamron Adaptall/Adaptall-2 | 50.7 mm | SLR | 24×36 mm | 1973-2006 | 14 | 29 | 3 | 26 | No camera uses Adaptall lenses natively, intended to be used with mount adapters. Many lenses have revisions, only original optical formulas are counted. |
Arri Standard | 52.00 mm | cine | |||||||
Arri B | 52.00 mm | cine | |||||||
Arri PL | 52.00 mm | cine | |||||||
Leica S-mount | 53.00 mm | SLR | 45×30 mm | 1996– | |||||
Mini T-mount | 55.00 mm | SLR | 24×36 mm | 1957–1962 | Taisei, M37×0.75 | ||||
T-mount | 55.00 mm | SLR | 24×36 mm | 1962– | Tamron T-400, M42×0.75 (not to be confused with M42×1) | ||||
YS mount | 55.00 mm | SLR | 24×36 mm | –1969 | Sigma, Upsilon, Accura, Polaris, Sun, Aetna, Beroflex, Petri, Raynox, N.P.S., Formula, Dionar, Universal, Soligor, Yashica, Spiratone. M42×0.75 (not to be confused with M42×1) Same as T-mount but with aperture coupling | ||||
Mamiya 6 | 56.20 mm | Mirrorless | 6×6 cm | 1989–1995 | 3 | 0 | 0 | 0 | Rangefinder camera system, flange focal distance might not be precise. [18] |
Panavision PV-mount | 57.15 mm | cine | 1972– | 35 mm & 16 mm | |||||
Mamiya 7 | 59.00 mm | Mirrorless | 6×7 cm | 1995–2014 | 6 | 0 | 0 | 0 | Rangefinder camera system |
OCT-19 | 61.00 mm | cine | |||||||
Hasselblad H-mount | 61.63 mm | SLR | 6×4.5 cm | 2002– | for Hasselblad H System | ||||
Mamiya 645 | 63.30 mm | SLR | 6×4.5 cm | 1975– | |||||
Novoflex A-mount | 63.3 mm | SLR | (measured) "A"-type adapters for follow-focus system | ||||||
Contax 645 | 64.00 mm | SLR | 6×4.5 cm | 1999– | |||||
Zenza Bronica ETR | 69.00 mm | SLR | 6×4.5 cm | 1976–2004 | 17 | 2 | |||
Pentax 645 | 70.87 mm | SLR | 6×4.5 cm | 1984– | 25 | 8 | 2 | 2 | |
Rollei SLX | 74.00 mm | SLR | 6×6 cm | 1976–2005 | |||||
Pentacon Six | 74.1 mm | SLR | 6×6 cm | 1956–1992 | Used also by Exakta 66 and Kiev 60 series cameras | ||||
Hasselblad V-mount | 74.90 mm | SLR | 6×6 cm | 1957–2013 | for Hasselblad V system | ||||
Kowa Six/Super 66 | 79.00 mm | SLR | 6×6 cm | 1968–1974 | 9 | 0 | |||
Hasselblad 1000F & 1600F | 82.10 mm | SLR | 6×6 cm | 1948–1957 | |||||
Salyut/Kiev mount | 82.10 mm | SLR | 6×6 cm | 1972–1980 | Used by Salyut-S/Салют-C, Zenit/Zenith-80, Kiev 88 cameras | ||||
Pentax 6×7 | 84.95 mm [19] or 85.00 mm | SLR | 6×7 cm | 1969–1999 | 25 | 2 | 3 | ||
Zenza Bronica SQ | 85.00 mm | SLR | 6×6 cm | 1980–2003 | 14 | ||||
Zenza Bronica GS | 85.00 mm | SLR | 6×7 cm | 1983–2002 | 9 | 0 | 2 | ||
Zenza Bronica S2A | 101.70 mm | SLR | 6×6 cm | 1959–1980 | |||||
Rollei SL66 | 102.80 mm | SLR | 6×6 cm | 1966–1992 | |||||
Mamiya RZ | 105.00 mm | SLR | 6×7 cm | 1982– | |||||
Mamiya RB | 112.00 mm | SLR | 6×7 cm | 1970– | |||||
Ricoh 126C-Flex | 62.22 mm | SLR | 24×24 mm | 1968-1969 | |||||
16-SP | 52 mm [20] | Cine | 16 mm | 1965-1991 | Used on the Soviet Kinor 16 and Krasnogorsk cameras | ||||
Kiev-16U | 31 mm [21] | Cine | 16 mm | 3 | Used on the Soviet Kiev-16U camera | ||||
1KSR-1M | 57 mm [22] | Cine | 35 mm | Used on the Soviet Konvas-1M, 7M, Automat cameras | |||||
1KSR-2M | 61 mm [22] | Cine | 35 mm | Used on the Soviet Konvas-2M, 8M, Kinor-35 cameras |
Flange focal distance is one of the most important variables in a system camera, as lens seating errors of as little as 0.01 mm will manifest themselves critically on the imaging plane and focus will not match the lens marks. Professional movie cameras are rigorously tested by rental houses regularly to ensure the distance is properly calibrated. Any discrepancies between eye focus and measured focus that manifest themselves across a range of distances within a single lens may be collimation error with the lens, but if such discrepancies occur across several lenses, it is more likely to be the flange focal distance or the ground glass (or both) that are misset.
Due to research on optimal flange focal distance settings, it is currently considered better for flange focal distance to be set to somewhere within the film's emulsion layer, rather than on the surface of it. Therefore, the nominal flange focal depth will be equivalent to the distance to the ground glass, whereas the actual flange focal depth to the aperture plate will in fact be ~0.02 mm less.
A single-lens reflex camera (SLR) is a camera that typically uses a mirror and prism system that permits the photographer to view through the lens and see exactly what will be captured. With twin lens reflex and rangefinder cameras, the viewed image could be significantly different from the final image. When the shutter button is pressed on most SLRs, the mirror flips out of the light path, allowing light to pass through to the light receptor and the image to be captured.
A rangefinder camera is a camera fitted with a rangefinder, typically a split-image rangefinder: a range-finding focusing mechanism allowing the photographer to measure the subject distance and take photographs that are in sharp focus.
A camera lens is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically.
Carl Zeiss AG, branded as ZEISS, is a German manufacturer of optical systems and optoelectronics, founded in Jena, Germany in 1846 by optician Carl Zeiss. Together with Ernst Abbe and Otto Schott he laid the foundation for today's multinational company. The current company emerged from a reunification of Carl Zeiss companies in East and West Germany with a consolidation phase in the 1990s. ZEISS is active in four business segments with approximately equal revenue in almost 50 countries, has 30 production sites and around 25 development sites worldwide.
A fisheye lens is an ultra wide-angle lens that produces strong visual distortion intended to create a wide panoramic or hemispherical image. Fisheye lenses achieve extremely wide angles of view, well beyond any rectilinear lens. Instead of producing images with straight lines of perspective, fisheye lenses use a special mapping, which gives images a characteristic convex non-rectilinear appearance.
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 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.
The M42 lens mount is a screw thread mounting standard for attaching lenses to 35 mm cameras, primarily single-lens reflex models. It is more accurately known as the M42 × 1 mm standard, which means that it is a metric screw thread of 42 mm diameter and 1 mm thread pitch.
The Pentax K-mount, sometimes referred to as the "PK-mount", is a bayonet lens mount standard for mounting interchangeable photographic lenses to 35 mm single-lens reflex (SLR) cameras. It was created by Pentax in 1975, and has since been used by all Pentax 35 mm and digital SLRs and also the MILC Pentax K-01. A number of other manufacturers have also produced many K-mount lenses and K-mount cameras.
Tilt–shift photography is the use of camera movements that change the orientation or position of the lens with respect to the film or image sensor on cameras.
A C mount is a type of lens mount commonly found on 16 mm movie cameras, closed-circuit television cameras, machine vision cameras and microscope phototubes.
The Sigma SA-mount is a lens mount by the Sigma Corporation of Japan for use on their autofocus single-lens reflex and mirrorless cameras. It was introduced with the SA-300 in 1992. Originally, the SA-mount was a dual-bayonet mount with inner (SA-IB) and outer (SA-OB) bayonets, the latter being a feature intended to mount heavy telephoto lenses, but never utilized by Sigma and consequently dropped with the release of the SD14 in 2007.
Lens speed is the maximum aperture diameter, or minimum f-number, of a photographic lens. A lens with a larger than average maximum aperture is called a "fast lens" because it can achieve the same exposure as an average lens with a faster shutter speed. Conversely, a smaller maximum aperture is "slow" because it delivers less light intensity and requires a slower (longer) shutter speed.
The T-mount is a standard lens mount for cameras and other optical assemblies. The usual T-mount is a screw mount using a male 42×0.75 metric thread on the lens with a flange focal distance of 55 mm and a mating female 42mm thread on a camera adapter or other optical component. This thread form is referred to as T-thread.
This article details lensesfor single-lens reflex and digital single-lens reflex cameras. The emphasis is on modern lenses for 35 mm film SLRs and for "full-frame" DSLRs with sensor sizes less than or equal to 35 mm.
The Micro Four Thirds system is a standard released by Olympus Imaging Corporation and Panasonic in 2008, for the design and development of mirrorless interchangeable lens digital cameras, camcorders and lenses. Camera bodies are available from Blackmagic, DJI, JVC, Kodak, Olympus, OM System, Panasonic, Sharp, and Xiaomi. MFT lenses are produced by Cosina Voigtländer, Kowa, Kodak, Mitakon, Olympus, Panasonic, Samyang, Sharp, Sigma, SLR Magic, Tamron, Tokina, TTArtisan, Veydra, Xiaomi, Laowa, Yongnuo, Zonlai, Lensbaby, Venus Optics and 7artisans amongst others.
The Fujica X-mount was a lens mount created by Fujifilm in the late 1970s and early 1980s for the new Fujica SLR lineup: AX-1, AX-3, AX-5, AX Multi, STX-1, STX-1N, STX-2, MPF105X, MPF105XN. It replaced the M42 screw mount used on their earlier SLRs.
The E-mount is a lens mount designed by Sony for their NEX and ILCE series of camcorders and mirrorless cameras. The E-mount supplements Sony's α mount, allowing the company to develop more compact imaging devices while maintaining compatibility with 35mm sensors. E-mount achieves this by:
The Pentax Q series is a series of mirrorless interchangeable-lens cameras made by Pentax and introduced in 2011 with the initial model Pentax Q. As of September 2012, it was the world's smallest, lightest interchangeable lens digital camera. The first models used a 1/2.3" back-illuminated sensor CMOS image sensor. The Q7, introduced in June 2013, uses a larger 1/1.7" type sensor. The Q system is now discontinued.
The Pentax Q is a mirrorless interchangeable-lens camera introduced by Pentax on June 23, 2011.
In photography and videography, a lens adapter is a device that enables the use of camera and lens combinations from otherwise incompatible systems. The most simple lens adapter designs, passive lens adapters provide a secure physical connection between the camera and the lens. Some passive adapters may include a mechanism for manual iris control. So called, active lens adapters will include electronic connections, enabling communication between the lens and the camera.