The Sigma 120-300mm f/2.8 DG OS HSM Lens for Canon is a telephoto zoom lens featuring a fast, constant f/2.8 maximum aperture. This lens is the first lens designed under Sigma's new Sports line of lenses, making it well-suited for fast-moving subjects such as wildlife, nature, aviation, racing, and other similar situations. Featuring a dust- and splash-proof construction, this lens is ideally-suited for use in outdoor and adverse conditions. Its design features rubber focus and zoom rings as well as conveniently located mode switches to enhance usability with the lens. A built-in Optical Stabilizer provides a four-stop-equivalent reduction in the appearance of camera shake, helping to enable better handheld usage and low-light shooting. The Hyper Sonic AF Motor provides fast, smooth, and quiet auto focusing for faster performance that also benefits video recording.