The Sigma 120-300mm F2.8 EX APO IF HSM AutoFocus Zoom Lens has a large aperture F2.8 300mm lens that allows you to determine the picture composition you want without having to change your vantage point. Its 2 Special Low Dispersion (SLD) glass elements in the front lens group and one in the rear group are for excellent correction of chromatic aberration, and since the front lens group does not rotate, the lens accepts a circular polarizing filter. The optical materials used in this lens are lead- and arsenic-free ecological glass. For use with Canon cameras.