Olympus Zuiko 50-200mm f/2.8-3.5 Digital ED SWD Lens for Olympus Digital SLR Cameras
The Zuiko Digital ED 50-200mm f2.8-3.5 SWD lens is a high-performance super-telescopic zoom lens that features, for the first time, the SWD (Supersonic Wave Drive) autofocus system and covers a zoom range equivalent to 100 to 200mm of a 35mm camera lens. ED lens elements are used extensively to correct the color blurring that can occur when telescopic lenses are extended to their maximum focal length, while the digital-dedicated design ensures high-definition performance with clear, crisp images from edge to edge. Close-up shooting capability is also superb, with a minimum shooting distance of just 1.2 meters throughout the zoom range.Autofocus is powered by Olympus’ breakthrough SWD, enabling this lens to achieve an AF speed about up to two times faster than the previous ED 50-200mm f2.8-3.5 model. The ideal partner for the E-3, this lens maximizes that camera’s high-speed autofocus capability, and with its superior tracking capability, this lens is ideal for sports photography and outdoor shooting applications.About Supersonic Wave Drive TechnologyOlympus-proprietary SWD technology has enabled an ultra-fast, whisper-quiet, high-precision AF system. Two compact, high-powered Supersonic Wave Drive devices power autofocus at an ultra-high speed by exciting unique elliptical oscillations, while an ultra-compact 5.3mm x 4.3mm optical encoder detects and controls the lens drive position using direct rotation detection without reduction gear. This  enables it to achieve a level of precision that’s accurate to 5 microns (5/1000 mm). When used in combination with the new E-3, which offers improved AF computation and lens-body communication rates, the SWD motors provide the fastest focusing speed of approximately 170 ms (0.17 seconds).