Specially designed for digital SLR cameras with an APS-C size image sensor, this large aperture f/2.8 lens has a compact and lightweight construction of 76.3mm (3.0 ) in diameter, 132.6mm (5.2 ) in length and weighing just 780g (27.5oz). The incorporation of the very latest optical technology gives optimum lens performance providing excellent correction for flare, ghosting and all types of aberrations. High image quality is assured throughout the entire zoom range. Four SLD (Special Low Dispersion) glass elements are used for utmost correction of chromatic aberrations. The HSM (Hyper Sonic Motor) system ensures quiet and high-speed auto focusing with full time manual focus override. The addition of the 1.4x EX DG APO or 2x EX DG APO Tele Converters (optional extras) produces a 70-210mm f/4 AF tele-zoom lens and a 100-300mm F5.6 AF ultra-telephoto zoom lens respectively.