Pentax K 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 mm
45.5 mm
| Name | Sensor format | Sensor crop | AF support | Year | Notes |
|---|---|---|---|---|---|
K | Full frame | 1.00 | No | 1975 | |
KA | Full frame | 1.00 | No | 1983 | the first K mount with electronic contacts |
KAF | APS-C | 1.52 | motor in camera | 1989 | |
KAF | Full frame | 1.00 | motor in camera | 1989 | |
KAF2 | APS-C | 1.52 | motor in camera, motor in lens | 1991 | power contacts added for power zoom or AF |
KA2 | Full frame | 1.00 | No | 1997 | |
KAF3 | Full frame | 1.00 | motor in lens | 2007 | |
KAF3 | APS-C | 1.52 | motor in lens | 2007 | |
KAF4 | Full frame | 1.00 | motor in lens | 2016 | like KAF3 but with electromagnetic aperture control |