Sigma 100-300mm f/4 APO D EX HSM IF is a superb telephoto zoom lens. The internal focusing lens provide a large f/4 aperture at all focal lengths. The integrated Hyper Sonic Motor (HSM) ensures quiet, high speed and precise autofocusing while Super Multi-Layer Coating minimizes flare and ghosting. Four SLD glass elements provide excellent color correction and sharpness throughout the entire zoom range. Multi-layer lens coating technology and lens design formula reduces flare and ghosting. Removeable rotating tripod collar and rear insertion 82mm filters with provision for easy rotation of polarizing filters.