The Sigma 24-70mm f/2.8 DG OS HSM Lens for Canon EF is a versatile zoom lens that covers wide-angle to portrait-length range of focal lengths. It has an optical design is used that incorporates three SLD elements and four aspherical elements to reduce chromatic and spherical aberrations, as well as color fringing, distortions, and other anomalies for greater clarity and sharpness. A Super Multi-Layer Coating has also been applied to suppress lens flare and ghosting for accurate color fidelity and high contrast, and a protective coating has been applied to the front element, too, to benefit working in harsh climates. Additionally, extending its versatility, a constant f/2.8 maximum aperture affords consistent performance throughout the zoom range as well as greater control over depth of field.