Sigma’s OS system allows the use of shutter speeds up to 4 stops slower than would otherwise be possible. For Sony and Pentax mounts, the built-in OS function of this lens can be used even if the camera body is equipped with an anti-shake system; as compensation for camera shake is visible in the viewfinder, the lens allows the photographer to easily check for accurate focus and ensure there is no subject movement.
Two “F” Low Dispersion (FLD) glass elements, offering performance equal to fluorite glass, and three Special Low Dispersion (SLD) glass elements provide excellent correction of colour aberration, while Sigma’s Super Multi-Layer Coating reduces flare and ghosting. High image quality is assured throughout the entire zoom range, and an optimum optical power layout provides superior quality in all shooting ranges from close-up to infinity.
The incorporation of a Hyper Sonic Motor (HSM) ensures quiet, high-speed auto focus with full-time manual focusing capability. The lens has a minimum focusing distance of 140cm throughout the entire zoom range and a maximum magnification ratio of 1:8. The rounded, 9-blade diaphragm creates an attractive blur for out of focus backgrounds. Equipped with a Petal-type hood, this lens also includes a dedicated hood adpator for digital cameras with an APS-C size image sensor, which expands the length of the lens hood.
The suggested retail price of the Sigma APO 70-200 F2.8 EX DG OS HSM lens is to be announced; the lens will be available in Canada beginning in May 2010 (for Canon mount).