Sigma 24-70mm f/2.8 DG OS HSM ArtA versatile zoom for everyday shooting, the 24 70mm f 2. 8 DG OS HSM Lens from Sigma covers a useful wide angle to portrait length range of focal lengths to suit shooting in a variety of environments. As part of the esteemed Art series of lenses, a sophisticated 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