The Pentax SMC DA 50-200mm f/4-5.6 ED WR is an impressive lightweight and compact mid-range 4x telephoto zoom lens. Ideal for the photographers desiring a broad zoom range without the pressure of heavier lens. Simple yet functional design of the SMC DA 50-200mm f/4-5.6 ED WR concerts Extra-low Dispersion glass element and two aspherical lens elements for true-to-life image reproduction. Its lens construction is comprised of 11 elements in 10 groups and has an equivalent 76.5-307mm focal length in 35mm format. The lens offers Pentax's Quick-shift focus system ensuring swift shifting from autofocus to manual focus using the focus ring and weather resistant design to repel rain and dust. Designed to fit Pentax DSLRs with APS-C 23.5x15.7mm CCD sensors for optimal performance, the lens also features Super Protect Coating.