A CPC Phase 2 28/2.8 wide macro is almost identical to a Takumar-A 28/2.8. There seems to be general agreement on the Forum that CPC lenses were made by the Pentax lens plant that made Cosmicars, Takumar-As and Pentax-As. So, I think my CPC qualifies as a Pentax. It certainly looks like a Pentax. Optically, it is exceptionally sharp at close distances. I haven't had a chance to test it out on longer shots yet. My copy is in Nikon F mount complete with rabbit ears, and has a Nikon-like 52mm filter thread. I wonder what other third-party lenses of the day were coming out of the Cosmicar plant.