The Pentax SMC-DA* 55mm f/1.4 SDM is a prime lens designed for Pentax DSLRs with APS-C sized sensors. The DA* 55mm f/1.4 SDM lens is great for portrait photography. This lens features Aero Bright Coating designed to deliver exceptional flare control and Pentax's Super Protect coating optimized to repel dust, water, and oil based material. The lens construction consist of nine elements in eight groups that includes the floating focus operation for polish performance at close distances. The lens is lightweight and compact weighing 13.23oz.