The 70-400mm f/4-5.6 G Alpha A-Mount Telephoto Zoom Lens from Sony is a 5.7x super telephoto lens, specifically designed for the Sony Alpha SLR series. When mounted to cropped Sony APS-C format Alpha DSLRs, its focal length becomes the 35mm equivalent of a 105-600mm super telephoto zoom lens.
As part of the G series of high quality lenses, the SAL-70400G is designed to deliver extremely sharp performance across its wide focal length range, and it features a high-speed SSM (SuperSonic-Wave Motor) for autofocus speed and precision. The focus-mode/range switch and three focus-hold buttons provide enhanced operability. And when used with the Alpha 900 SLR camera, the AF hold buttons can be customized to activate the intelligent preview function.