This telephoto zoom lens incorporates Sigma's original OS (Optical Stabilizer) function. Three SLD (Special Low Dispersion) glass elements provide excellent correction for chromatic aberration. This lens is equipped with the rear focus system that minimizes fluctuation of aberration caused by focusing. It provides optimum image quality throughout the entire zoom range. The super multi-layer coating reduces flare and ghosting. High image quality is assured throughout the entire zoom range.