This telephoto zoom lens provides a large constant F4 maximum aperture at all focal lengths. The use of Apochromatic design and 4 SLD (The Special Low

This telephoto zoom lens provides a large constant F4 maximum aperture at all focal lengths. The use of Apochromatic design and 4 SLD (The Special Low Dispersion) glass elements (two SLD glass elements are utilized in the front lens group and two in the rear group) for full correction of chromatic aberration and providing a high level of optical performance. The AF drive for Sigma SA, Canon and Nikon cameras is equipped with silent, responsive and high speed HSM (Hyper Sonic Motor) as well as fulltime manual focus.