Sigma 17-50mm f/2.8 EX DC OS HSM Zoom Lens (for Canon DSLRs with APS-C Sensors) Bundle Includes Manufacturer Accessories + 3 PC Filter Kit + Lens Cap + Lens Pen + Cap Keeper + Microfiber Cloth For Canon DSLRs with APS-C Size Sensors; 4 Stops of Anti-Shake (OS) Compensation Aperture of f/2.8 throughout Zoom Range; Accepts 77mm Filters Ultra Compact (Only 3.6", 91.8mm Long); Multi-Layered Lens Coating Excellent Correction for Aberrations; Hyper-Sonic Motor for Quiet/Fast AF Close Focusing Distance of 11" (28cm); Weighs Only 19.9 oz (565 g)