Pentax K lens mount

Pentax introduced the K-mount in 1975 for full frame (35 mm) sized film cameras, then evolved in a lot of variations essentially for electonic communications between camera and lens (KF, KA, KA2, KAF, KAF2, KAF3, KAF4) - details in this article.

The K-mount is used in lenses for both full frame and APS-C sensor cameras.

An interesting article on K-mount evolution is at this link.

Sigma stopped production of K-mount lenses in September 2019.

Yes
48.0
45.5
NameSensor formatSensor cropAF supportYearNotes
K
Full frame1.00No1975
KA
Full frame1.00No1983
the first K mount with electronic contacts
KAF
APS-C1.52motor in camera1989
KAF
Full frame1.00motor in camera1989
KAF2
APS-C1.52motor in camera, motor in lens1991
power contacts added for power zoom or AF
KA2
Full frame1.00No1997
KAF3
Full frame1.00motor in lens2007
KAF3
APS-C1.52motor in lens2007
KAF4
Full frame1.00motor in lens2016
like KAF3 but with electromagnetic aperture control
1620