Merkin
For the Weekend
my father is a long time pentax/ricoh user, and he told me that some non-ricoh non-pentax k mount lenses will work, and some wont, and it requires examining the mount from lens to lens (for a while, the ricoh was the more advanced camera, so some aftermarket lenses were allegedly made for full functionality with the ricoh, at least according to my father). he may have been given erroneous info, but as a solid rule of thumb to be on the safe side, it is recommended that you stick with the pentax brand k mount lenses.