The Pentax K-Mount: A Comprehensive Overview

The Pentax K-mount, also referred to as the “PK-mount”, stands as a testament to the evolution of camera technology.

Introduced by Pentax in 1975, this bayonet lens mount was designed for 35 mm single-lens reflex (SLR) cameras. Over the years, it has been incorporated into all Pentax 35 mm and digital SLRs, including the MILC Pentax K-01.

Use of the K-mount isn’t limited to Pentax alone. Several other manufacturers have produced Pentax K-mount lenses and cameras.

  • A simple bayonet connection with three tabs.
  • Introduced with the K series of cameras.
  • Mechanical linkage with the camera involving the aperture.
  • Supported by K series, M series (except ME F), and LX cameras.
  • Pentax’s first attempt at an autofocus system.
  • Only one camera and one lens used this mount: Pentax ME F and SMC Pentax-AF 35-70/2.8.
  • Derived from the original K-mount.
  • Allows the lens’s aperture to be set by the body.
  • Introduced in 1983 and supported by A-series and P-series bodies.
  • A refined attempt at adding auto-focus to lenses.
  • Introduced a small drive shaft to the KA-mount.
  • Variations of the KAF-mount with added functionalities like electrical contacts and digital information transmission.
  • A variation by Ricoh, supporting Ricoh’s own implementation of shutter priority and auto exposure modes.
SMC Pentax-M 50mm f/2 Lens Mount for the Pentax K-mount
SMC Pentax-M 50mm f/2 Lens Mount

The Pentax K-mount is a bayonet style lens mount with 3 tabs for mounting. It was originally designed to be used on 35mm film full frame SLR cameras.

Later versions of the lens mount had electrical contacts and a drive shaft for autofocus added. The drive shaft would connect to an autofocus motor inside a camera body.

The flange focal distance is 45.46 mm. This is the same distance as the M42 mount. This was done so that Pentax M42 lenses could be used on K-mount cameras with a lens adapter. Pentax as well as third parties made lens adapters.

However, due to the relatively large flange distance for a 35mm SLR camera, Pentax K-mount lenses cannot be easily adapted to other SLR or DSLR cameras. There are K-mount lens adapters for all mirrorless camera mounts.

To get around the flange distance not being large enough, there are some adapters that have glass optics to allow for focus to infinity. The optics are to compensate for the lens being further away from the imaging plane than it was designed for. Unfortunately, the optics are of poor quality, which greatly reduces image quality.

  • K2 (1975–1980)
  • K2 DMD (1976–1980)
  • KX (1975–1977)
  • KM (1975–1977)
  • K1000 (1976–1997)
  • ME (1976–1980)
  • MX (1976–1985)
  • ME Super (1979–1984)
  • MV (1979–1982)
  • MV1 (1979-1982)
  • ME F (1981–1988)
  • MG (1982–1985)
  • LX (1980–2001)
  • Super A / Super PROGRAM (1983–1987)
  • Program A / Program PLUS (1984–1988)
  • A3/A3000 (1985–1987)
  • P5/P50 (1986–1989)
  • P3/P30 (1985–1988)
  • P3n/P30n (1988–1990)
  • P30t (1990–1997)
  • SFX/SF1 (1987–1989)
  • SFXn/SF1n (1989–1993)
  • SF7/SF10 (1988–1993)
  • Z-10 (1991)
  • Z-1 (flagship model) (1991)
  • Z-20 (1992)
  • Z-50 (1992)
  • Z-1P (flagship model) (1994)
  • Z-5P (1994)
  • Z-70 (1995)
Pentax ZX-50 35mm Film SLR
Pentax ZX-50 35mm Film SLR
  • MZ-S (Flagship model)
  • MZ-3
  • MZ-5 MZ-5n
  • MZ-10
  • MZ-7
  • MZ-6/ZX-L
  • MZ-M
  • MZ50
  • MZ30
  • MZ60
  • *ist (2003–2006)
Pentax 100D DSLR with SMC Pentax-DA f/4-5.6 55-200mm Zoom Lens
Pentax 100D with SMC Pentax-DA f/4-5.6 55-200mm Zoom Lens
  • *ist D Flagship model (2003–2006)
  • *ist DS (2004–2005)
  • *ist DS2 (2005–2006)
  • *ist DL (2005–2006)
  • *ist DL2 (2006)
  • Pentax K100D (2006–2007)
  • Pentax K110D (2006–2007)
  • Pentax K10D (2006–2008)
  • Pentax K10D Grand Prix (limited edition) (2007)
  • Pentax K100D Super (2007–2008)
  • Pentax K200D (2008–2009)
  • Pentax K20D (2008–2009)
  • Pentax K-m (Pentax K2000 in U.S.) (2008–2009)
  • Pentax K-7 (2009–2010)
  • Pentax K-x (2009–2011)
  • Pentax K-r (2010–2012)
  • Pentax K-5 (2010–2012)
  • Pentax K-01 (2012–2013)
  • Pentax K-30 (2012–2013)
  • Pentax K-5 II (2012–2014)
  • Pentax K-5 IIs (2012–2014)
  • Pentax K-50 (2013–2016)
  • Pentax K-500 (2013–2014)
  • Pentax K-3 (2013–2015)
  • Pentax K-S1 (2014–2016)
  • Pentax K-S2 (2015–present)
  • Pentax K-3 II (2015–2018)
  • Pentax K-1 (2016–2018)
  • Pentax K-70 (2016–2022)
  • Pentax KP (2017–2021)
  • Pentax K-1 II (2018–present)
  • Pentax K-3 III (2021–present)
  • Pentax KF (2022–present)

Numerous cameras have utilized the K-mount over the years. Some notable ones include:

  • CE-4, CE-4s, CA-4, CA-4s, CM-4, CM-4s
  • CE-5, CG-5, CM-5, CP-5, CP5s
  • CP-6, CP-X
  • CP-7m, CM-7
  • CP-9AF
  • C1, C1s
  • CS-2, CS-3
  • CT-10, CT-1A, CT-20, CT-7, CT-1G, CT-9, CT-4
  • CE-4, CE-4s, CE-5
  • HS-1
  • HS-2
  • HS-4
  • HS-10
  • HS-40
  • KE 5
  • MS-1
  • MS-2 Super
  • MS-3
  • Porst Compact Reflex OC
  • Porst Compact Reflex OCN
  • KR-5
  • KR-5 Super
  • KR-5 Super II
  • KR-5 III
  • KR-10
  • KR-10 Super
  • KR-10M
  • KR-30sp
  • XR-1
  • XR-1s
  • XR-2
  • XR-2s
  • XR-500
  • XR500 auto
  • XR-6
  • XR-7
  • XR-10
  • XR-P
  • XR-20sp
  • XR-Solar
  • XR-M
  • XR-F
  • XR-P
  • XR-S
  • XR-X
  • XR-X 3PF

These cameras were made by Ricoh or Chinon. The majority of the models were rebadged, with those models being referenced in parentheses.

  • KS-1000 (Ricoh XR-1)
  • KS-500 (Ricoh XR-500)
  • KS Auto (Ricoh XR-2S)
  • KS-1
  • KS-2 (Ricoh XR-7)
  • KSX (Ricoh KR-10)
  • KSX-P (Chinon CP-5)
  • KS Super
  • KS Super II
  • V635
  • V4000
  • V3800N
  • V3000N
  • V3000s
  • V2000
  • XV1 (rebadged Cosina CT-1)
  • XV20 (rebadged Cosina CT-20)

The Pentax K-mount has seen a plethora of lenses from various manufacturers. The best Pentax K-mount lenses are going to be those produced by Pentax and Carl Zeiss.

Table of K-Mount Lens Variations:

Series Prime Lenses Zoom Lenses
K series 34 7
M series 22 8
A series 19 11
F series 7 10
FA series 12 17
D FA series 3 5
DA series 4 18
DA Limited 10 1
DA* series 3 4
  • The first generation of Pentax K-mount lenses.
  • Not officially referred to as K series lenses but are often designated as such to distinguish them from later K-mount lenses.
  • Exclusively manual focus lenses with no electronic features.
  • Name starts with either upper case “SMC” or lower case “smc”, representing the Super-Multi-Coated lens coating.
  • Followed the K series lenses.
  • Manual K-mount lenses without electronic features.
  • Generally smaller in size to match compact camera bodies like the Pentax MX and Pentax ME Super.
  • Introduced “automatic” aperture settings.
  • Had an aperture ring but also an “A” mode, allowing the camera to control the aperture automatically.
  • First autofocus lenses for Pentax.
  • Screw-drive type autofocus.
  • Featured an aperture ring for manual control.
  • Designed for full-frame film SLR cameras.
  • Screw-drive type autofocus.
  • Some, like the FA Limited lenses, are high-quality metal primes.
  • Similar to the FA series but lacked an aperture ring.
  • Coated for digital cameras but also support older 35mm camera formats.
  • Some are weather resistant.
  • Designed for Pentax digital cameras with an APS-C digital sensor.
  • Lacks an aperture ring.
  • Lighter and cheaper versions of DA series zoom lenses.
  • Designed for Pentax digital SLRs.
  • Higher quality optics and better weather sealing.
  • High-quality prime lenses with metal housing.
  • Compact in design.

Some notable third party K-mount lenses include:

  • Access: 28 mm f2.8 P-MC Macro, 75–300 mm f5.6 PMC Zoom.
  • Angenieux: 70–210 mm f3.5.
  • Agfa: Agfa Color 50 mm f1.4.
  • Arsat: PCS Arsat 35 mm f2.8 Shift Lens.
  • Carl Zeiss Jena: 20 mm f4, 28 mm f2.8, 70–210 mm f4.5, 75–300 mm f4.5-5.6 ED IF MC Macro.
  • Carl Zeiss: Introduced a line of lenses for the K-mount in 2008.

The Pentax K-mount’s legacy is a testament to its adaptability and the vision of its creators. Its versatility has allowed it to remain relevant in the ever-evolving world of photography, making it a favorite among both amateur and professional photographers.

Whether you’re a vintage camera enthusiast or a modern-day photographer, the K-mount’s rich history and wide range of compatible equipment make it an attracive mount for any photographer.