The Olympus Zuiko ED 50-200mm f/2.8-3.5 SWD lens is a professional telephoto zoom lens and is considered one of the lightest and most compact of its kind with excellent light-gathering power. The powerful Zuiko Digital ED 50-200mm 1:2.8-3.5 SWD zoom lens offers an equivalent range of 100 - 400mm on a 35mm film camera and fast, silent autofocusing SWD system. The lens consist of 16 elements in 15 groups with three ED elements. ED elements corrects blurring that may happen when telephoto lenses are expanded to their maximum focal length. The exclusive design promises ultra-definition performance with clear, sharp images from edge to edge.