Pentax SMC P-A 645 150mm f/3.5

Manufacturer's Description:

"The PENTAX SMCP-A 645 150mm f/3.5 manual focus lens features an automatic setting on the aperture ring. It offers a 150mm focal length (equivalent to approximately 100mm in the 35mm format), a minimum focusing distance of 4 ft. (1.2m) and a large lens hood with a polarizing filter adjustment window. Like all PENTAX lenses, this lens is treated with the acclaimed smc coating for maximum light transmission, sharp definition, and high contrast while minimizing flare and ghost imaging."