The Versatile Telephoto zoom has a focal length range of 112-320mm and is intended for full-frame Canon EF-mount DSLRs, but it can also be used with APS-C models. Consistent performance across the zoom range and significant depth of field control for selective focus techniques are provided by the bright constant f/2.8 maximum aperture. For excellent clarity and color fidelity, one fluorite element and five ultra-low dispersion glass elements significantly lessen chromatic aberrations and color fringing. To maintain light transmission and high contrast under intense lighting conditions, lens elements have been coated with an Air Sphere Coating (ASC) to lessen backlit flaring and ghosting. By reducing the appearance of camera shake by up to 3.5 shutter speed stops, an optical image stabilizer improves the