Originally posted by jatrax Be aware that not all k-mount will work without issues. Ricoh used the k-mount for their cameras back in the film days but they also added a pin called a "Ricoh Pin" which can sometimes get stuck on Pentax cameras.
This caution cannot be understated. Despite assurance from various forum members, the "Ricoh Pin" hazard is a serious potential hazard. Unfortunately, the degree of peril is difficult to gauge without some experience with the mount. It is enough to say that in the worst case some Ricoh-variant K-mount lenses may be almost impossible to remove from a Pentax AF body (both film and digital) once mounted.
I would suggest avoiding the following:
- Rikenon-P (all models)
- Lenses marked PK/R on the barrel or the mount
- Lenses marked KR
- Lenses marked PKA/R
- K-mount lenses with "P" on the aperture ring rather than "A"
Other Rikenon/Ricoh lenses are perfectly safe.
The "pin" itself is sometimes an actual pin and other times a ball-contact. In both cases it is spring loaded and unfortunately has the same position on the mount as the Pentax AF screw drive. When mounted, the pin drops into the screw-drive well from which it may not be easily retracted. The ball type is much less prone to jamming than the pin type.
Note that Pentax developed its AF bodies some years after the Ricoh mount went to market, so this is a black mark against Pentax.
Steve
FWIW...rescuing a body with a jammed Ricoh pin usually involves careful use of an automotive feeler gauge slipped into the mount space between the lens and body. In one particularly bad case, the services of a repair shop were needed and the lens was subjected to a hack saw to cut it off the camera. The user then had to also pay to have the mirror box thoroughly cleaned to remove the shards.