The high performance DA* 200mm ED (IF) lens incorporates an SDM system which creates a smoother, quieter auto focus. Featuring a Quick-shift Focus System, switching from auto focus to manual is instantaneous. Developed specifically for PENTAX digital SLRs, the DA* 200mm ED (IF) SDM lens has PENTAX SP coating which protects the exposed lens elements, and a focal length equivalent to 300mm in the 35mm format. Weather and dust resistant, it's the perfect lens for extreme weather conditions. 200mm High performane telephoto lens,Weather resistant and dust resistant.