Sigma 200-500mm f/2.8 APO EX DG Ultra-Telephoto Zoom Lens for Canon DSLR Cameras

Ultra telephoto zoom lens; fast aperture of F2.8 at the 500mm and F5.6 at the 1000mm focal lengthDedicated "Attachment" ensures autofocusing at the 1000mm focal lengthSLD and three ELD glass elements provide high image quality from the maximum large apertureSupplied with 72mm filter holder at the rearFor Canon digital SLRs
Product DescriptionThis ultra telephoto zoom lens offers a fast aperture of F2. 8 at the 500mm focal length and F5. 6 at the 1000mm. It covers widely-used focal lengths

Source: Digital Camera and Video Store...