Flange focal distance

Last updated
Diagram illustrating the flange focal length of an SLR-type and a mirrorless-type camera Flange Focal Length (2 types camera).PNG
Diagram illustrating the flange focal length of an SLR–type and a mirrorless–type camera

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.

Contents

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.

Standard mounts

Typically, camera bodies with shorter flange focal distance can be adapted more readily to lenses with longer flange focal distance.

MountFlange
focal distance
TypeFormatProductionPrime lensesZoom lensesWide/tele convertersMount convertersComments
Samsung NX mini 6.95 mmMirrorless1"2014–2015211
Pentax Q-mount 9.2 mm [2] Mirrorless1/2.3" (6.17×4.55 mm) / 1/1.7"2011–20195301
M58×0.75 mm mount12 mmIndustrial24×36 mmIndustrial area and line scan cameras
D-mount 12.29 mmcine8 mm(8 mm movie cameras)
CS-mount 12.526 mm [3] [4] [5] TV1/4", 1/3", 1/2"(surveillance cameras)
Nikon Z-mount 16 mmMirrorless24×36 mm (FX)2018– 23 14 2 1 Lens count doesn't include 3rd party products.
APS-C (DX)2018– 1 5 Lens count doesn't include 3rd party products. Can use any of the 24x36 mm (FX) lenses and the FTZ/FTZ II mount adaptor.
DJI DL-mount 16.84 mm [6] MirrorlessSuper 352017–61For use on aerial drone and gimbal cameras.
Nikon 1-mount 17.00 mm [7] MirrorlessCX2011–2018381
C-mount 17.526 mm [8] cine / TV8 mm, 16 mm, 1/3", 1/2", 2/3", 1", 4/3"~1926–(Bolex, Eclair and Bell & Howell)
Fujifilm X-mount 17.7 mmMirrorlessAPS-C2012– 23 14 2 1 [9]
Canon EF-M-mount 18.00 mmMirrorlessAPS-C2012– 3 5 0 1
Sony E-mount 18.00 mmMirrorlessAPS-C2010– 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 mmcineSuper 352011–0203
24×36 mm2015–12
Micro Four Thirds System 19.25 mmMirrorless4/3"2008– 37 28 11
Hasselblad XCD mount 18.14 mm (+0.05/-0.00)MirrorlessMedium Format (127) 43.8×32.9 mm2017–1313for Hasselblad X System
Canon RF mount 20.00 mmMirrorless24×36 mm2018–12113
L-Mount [10] (Leica, Panasonic Lumix, Sigma, DJI)20.00 mmMirrorless24×36 mm, APS-C2014–1912The members of the L-mount alliance are Leica Camera, SIGMA, Panasonic, Ernst Leitz Wetzlar GmbH and DJI
LUMIX Panasonic [11] 20.00 mmMirrorless24×36 mm, APS-C2015–897L-mount system
JVC 1/3" bayonet mount 25.00 mmTV1/3" 3-CCD (5.24×2.94 mm)
Samsung NX-mount 25.50 mmMirrorlessAPS-C2010–201588
Fujifilm G-mount 26.7 mmMirrorlessMedium Format (127) 43.8×32.9 mm2017–721for Fujifilm GFX series cameras
Pentax Auto 110 27.00 mmSLR13×17 mm1978–19855100
RED ONE interchangeable mount 27.30 mmcine
Leica M-mount 27.8 (inner rails) <-> 27.95 (outer rails) mm [9] Mirrorless24×36 mm1954–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 [12] underwater24x36 mm1963-20016000this is the underwater scale focusing camera
M39×26tpi mount 28.80 mmMirrorless24×36 mmLeica M39×26tpi aka LTM (Leica Thread Mount) aka L39 (not to be confused with M39×1)
M39×1/28.8 mount 28.80 mm [13] Mirrorless24×36 mm1948-1978Zorki M39×1/28.8 for Zorki cameras (not to be confused with M39×1 and M39x26tpi)
Contax G-mount 29.00 mmMirrorless24×36 mm1994–20056101
Olympus PEN F (film)28.95 mmSLR18×24 mm1963–1972162
Hasselblad XPan 34.27 mmMirrorless24×36 mm & 24×65 mm1998–20033000Identical to Fujifilm TX series cameras and mount
Contax RF-mount 34.85 mmMirrorless24×36 mm
Nikon S-mount 34.85 mmMirrorless24×36 mm1947–2005
1/2" TV bayonet mount 35.74 mmTV1/2" 3-CCDJVC, Hitachi, Panasonic, others, but not Sony
Minolta V-mount 36.00 mmSLRAPS-H1996–19993501 Vectis S-1, Vectis S-100, Dimâge RD 3000
Sony 1/2" TV bayonet mount 38.00 mmTV1/2" 3-CCD
Olympus Four Thirds System 38.67 mmSLR4/3"2003–201712302
Aaton mount40.00 mmcine16 mm/S16
Panavision SP70-mount 38.00 mmcine2018–35 mm & 65 mm
Konica F-mount 40.50 mmSLR24×36 mm1960–196517000
Konica AR-mount 40.50 mmSLR24×36 mm1965–1988361610
Canon FL-mount 42.00 mmSLR24×36 mm1964–1971
Canon FD-mount 42.00 mmSLR24×36 mm1971–199010734
Start (Soviet SLR)42.00 mmSLR1958–1964
Minolta SR-mount 43.50 mmSLR24×36 mm1958–20016
Fujica X-mount 43.50 mmSLR24×36 mm1980–1985
Pentaflex (16 mm cameras) 44.00 mmcine
Canon EF-mount 44.00 mmSLR24×36 mm / APS-H / APS-C1987–4764
Canon EF-S-mount 44.00 mmSLRAPS-C2003– 2 9 00
Praktica B-mount 44.40 mmSLR24×36 mm1978–1990
Sigma SA-mount 44.00 mmSLR24×36 mm / APS-C1992–141924
M39x144.00 mm [14] Mirrorless24×36 mm1950sBraun Paxette rangefinder cameras
Kiev Automat 44.00 mm [15] SLR24x36 mm1960s-1980s6 [15] 1 [15]
Arri LPL44.00 mmcine25.54x36.70 mm2018-for Arri Alexa LF
Minolta/Konica Minolta/Sony A-mount 44.50 mmSLR24×36 mm1985– 42+0+17 50+2+13 6+0+2 2+0+0
APS-C2004–0+0+30+3+130+0+00+0+0
Rollei QBM 44.50 mm [16] SLR24×36 mm1970– Rollei, Voigtländer
Samsung Kenox mount 44.50 mmSLR24×36 mm1997–200212 (3?)00Although designed in 1990s, mount is manual-focus only; lenses mount and lock on a slightly modified Minolta A-mount adapters
Exakta 44.7 mm [17] SLR24×36 mm1936–1969
M39x145.20 mm [18] SLR24×36 mm1952–1968Early Russian SLRs (Zenit) (not to be confused with M39×26tpi and M39×1/28,8)
M37×1 45.46 mmSLR24×36 mm1952-1957Asahiflex I, Asahiflex IA (Tower 23), Asahiflex IIB (Tower 23/24), Asahiflex IIA (Tower 22)
M42×1 45.46 mmSLR24×36 mm1949–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 mmSLR / Mirrorless24×36 mm / APS-C1975–147 [19] 10883Used 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 mmSLR24×36 mm1974–20052453Used by some Contax and Yashica SLR cameras
Petri Bayonet 43.50 mmSLR24×36 mmPetri SLRs 1960-77.
Mamiya Z 45.50 mmSLR24×36 mm1980–
Kodak Retina DKL-mount 45.7 mmSLR / Mirrorless24×36 mm / 28×28 mm1958–1977 12+6 000DKL 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 mmSLR24×36 mm1958–1967 11+2 1 00DKL variants used by Bessamatic, Bessamatic deLuxe, Bessamatic m, Bessamatic CS, Ultramatic, Ultramatic CS
Braun Paxette Reflex DKL-mount 45.7 mmSLR / Mirrorless24×36 mmDKL 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 mmMirrorless24×36 mm 4+?000DKL 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-mount45.80 mmSLR24×36 mm1(measured); 230AF etc.
Olympus OM-mount 46.00 mmSLR24×36 mm1972–20023814
Nikon F-mount 46.50 mmSLR24×36 mm / APS-C1959– 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. [20]
Leica R-mount 47.00 mmSLR24×36 mm1964–2009
KMZ Zenit DKL-mount 47.58 mmSLR24×36 mm1964–1968 5 1 00Zenit/Зенит 4/5/6 "Байонет Ц", an unofficial DKL-mount variant
B4-mount 48.00 mmTV2/3" 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 mmSLR24×36 mm2000–20054501
Tamron Adaptall/Adaptall-2 50.7 mmSLR24×36 mm1973-20061429326No 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 mmcine
Arri B 52.00 mmcine
Arri PL 52.00 mmcine
Leica S-mount 53.00 mmSLR45×30 mm1996–
Mini T-mount 55.00 mmSLR24×36 mm1957–1962Taisei, M37×0.75
T-mount 55.00 mmSLR24×36 mm1962–Tamron T-400, M42×0.75 (not to be confused with M42×1)
YS mount 55.00 mmSLR24×36 mm–1969Sigma, 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 mmMirrorless6×6 cm1989–19953000Rangefinder camera system, flange focal distance might not be precise. [21]
Panavision PV-mount 57.15 mmcine1972–35 mm & 16 mm
Mamiya 7 59.00 mmMirrorless6×7 cm1995–20146000Rangefinder camera system
OCT-19 61.00 mmcine
Hasselblad H-mount 61.63 mmSLR6×4.5 cm2002–for Hasselblad H System
Mamiya 645 63.30 mmSLR6×4.5 cm1975–
Novoflex  [ de ] A-mount63.3 mmSLR(measured) "A"-type adapters for follow-focus system
Contax 645 64.00 mmSLR6×4.5 cm1999–
Zenza Bronica ETR 69.00 mmSLR6×4.5 cm1976–2004172
Pentax 645 70.87 mmSLR6×4.5 cm1984–25822
Rollei SLX 74.00 mmSLR6×6 cm1976–2005
Pentacon Six 74.1 mmSLR6×6 cm1956–1992Used also by Exakta 66 and Kiev 60 series cameras
Hasselblad V-mount 74.90 mmSLR6×6 cm1957–2013for Hasselblad V system
Kowa Six/Super 66 79.00 mmSLR6×6 cm1968–197490
Hasselblad 1000F & 1600F 82.10 mmSLR6×6 cm1948–1957
Salyut/Kiev mount 82.10 mmSLR6×6 cm1972–1980Used by Salyut-S/Салют-C, Zenit/Zenith-80, Kiev 88 cameras
Pentax 6×7 84.95 mm [22] or 85.00 mmSLR6×7 cm1969–19992523
Zenza Bronica SQ 85.00 mmSLR6×6 cm1980–200314
Zenza Bronica GS 85.00 mmSLR6×7 cm1983–2002902
Zenza Bronica S2A 101.70 mmSLR6×6 cm1959–1980
Rollei SL66 102.80 mmSLR6×6 cm1966–1992
Mamiya RZ 105.00 mmSLR6×7 cm1982–
Mamiya RB 112.00 mmSLR6×7 cm1970–
Ricoh 126C-Flex 62.22 mmSLR24×24 mm1968-1969
16-SP52 mm [23] Cine16 mm1965-1991Used on the Soviet Kinor 16 and Krasnogorsk cameras
Kiev-16U 31 mm [24] Cine16 mm3Used on the Soviet Kiev-16U camera
1KSR-1M57 mm [25] Cine35 mmUsed on the Soviet Konvas-1M, 7M, Automat cameras
1KSR-2M61 mm [25] Cine35 mmUsed on the Soviet Konvas-2M, 8M, Kinor-35 cameras
Vivitar TX 56.25 mmSLR24×36mm1976-1010Generic mount used to be attached on many cameras thanks to differents adapters

Precision

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.

Film use

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.

See also

References

  1. "FOCUS BACK ON BACK FOCUS". 30 May 2009.
  2. Archived 2012-03-19 at the Wayback Machine pentax.jp
  3. Hornberg, Alexander (2007-02-27). Handbook of Machine Vision. John Wiley & Sons. ISBN   9783527610143.
  4. "CS-Mount | Edmund Optics". www.edmundoptics.com. Retrieved 2018-07-28.
  5. "Flangeback Distances | Universe Optics". Universe Optics. Retrieved 2018-07-28.
  6. "DJI launches Zenmuse X7 Super 35mm camera module with Raw video capture". dpreview.com.
  7. "Camera Mounts Sorted by Register".
  8. "C-Mount vs. CS-Mount" (PDF). ikegami.com. Retrieved 4 August 2023.
  9. 1 2 "Lens accessories | Accessories". FUJIFILM X Series & GFX – Global. 11 January 2024.
  10. "L-mount Alliance Overview".
  11. "LUMIX Panasonic L-mount". Panasonic.com.
  12. "Nikonos Lenses on Nikon dSLR?". Photo.net Photography Forums. 21 January 2012.
  13. "The Camera ZORKI Instruction Manual?" (PDF).
  14. Discussion of Zenit and Braun Paxette mounts
  15. 1 2 3 Reinsalu, Armult (1987). "Lisad" [Extras]. In Iho, A; Kivi, A (eds.). Algajale fotograafile[For a beginner photographer] (in Estonian). Reviewed by Kunnar Allikvee, artistic editor H. Puzanov, technical editor K. Kuulmann, proofreaders S. Hiie and M. Mere. Tallinn: Valgus. p. 177. https://www.librarything.com/work/10549335/t/Algajale-fotograafile.
  16. Bertram Hönlinger, Carl Zeiss AG (2014): All Zeiss QBM lenses were designed for 44.5 mm. The 44.7 mm value found on some US sites is wrong.
  17. Wrotniak, J. Andrzej
  18. Zenit's mount history: M39x1/45,2
  19. "Zoom Lenses | PentaxForums.com". www.pentaxforums.com.
  20. Nikon F-Mount, nikonusa.com
  21. Ken Rockwell's Mamiya 6 page
  22. Camera Mounts Sorted by Register
  23. "16-SP (Krasnogorsk-2) adapters" . Retrieved 3 May 2024.
  24. "Industar-50 KIEV 16mm lens C mount ?". forum.mflenses.com. Retrieved 2024-05-03.
  25. 1 2 "Flange Focal Distances". Archived from the original on 2006-05-18. Retrieved 2024-05-03.