Sigma 17-50mm F2.8 EX DC OS HSM Lens for Canon (583101) with Wrist Strap + Cap Keeper + Deluxe Lens Cleaning Kit for Prints Constructed with 17 elements in 13 groups, it features FLD ("F" Low Dispersion) glass which is the highest level low dispersion glass available with extremely high light transmission. HSM (Hyper-Sonic Motor) ensures a quiet & high-speed auto focus. Deseigned for use with digital cameras with APS-C size sensors only. Ideal for many photo opportunities particularly landscapes and portraits. You can capture images with unique perspectives. Note: Vignetting will occur if the lens is used with digital cameras with image sensors larger than APS-C size or 35mm SLR cameras. 47th Street Photo is an Authorized Sigma USA Dealer. This item is covered by 4 Year Sigma USA Warranty.