Takumar is the name that Asahi Optical gave to its lenses, notably but not exclusively those for its own SLR cameras. Named after the Japanese-American portrait painter, Takuma Kajiwara (梶原啄磨, Kajiwara Takuma),[1] whose brother Kumao Kajiwara founded Asahi Optical.[2] The name adorned its lenses until 1975, when Asahi switched from the M42 screw mount to the bayonet K-mount. K-mount lenses were simply named "SMC Pentax". Some Takumar lenses were also made for the K-mount.