This lens is a large aperture standard zoom lens that is excellent for photojournalism and general pro photography. The lens covers focal lengths from 24mm wide angle to 70mm medium telephoto, with a bright viewfinder, and easy AF/MF all the way through. When used with Canon digital SLR cameras with APS-C size sensors, the focal length offered by this lens will be equivalent to 38-112mm, in 35mm SLR terms.
The Hyper Sonic Motor (HSM) ensures a silent, high-speed AF function as well as full-time manual focusing capability. This lens features Super Multi Layer Coating, which reduces flare and ghosting. DG is a designation Sigma uses on lenses featuring optical systems designed to meet the performance characteristics of digital SLR cameras. In addition, this lens has been redesigned and is now more compact and lighter than its predecessor.
DG Lens Design The improved DG lens design corrects for various aberrations. This lens is specially coated to get the best color balance while also cutting down on ghosting caused by reflections from the digital image sensor. HSM (Hyper Sonic Motor) Hyper Sonic Motor provides smooth, silent AF with fulltime manual focus override ELD & SLD Elements This lens uses three ELD (Extraordinary Low Dispersion) elements and two SLD (Special Low Dispersion) elements for correction against chromatic aberrations 9-Blade Aperture The rounded 9-blade diaphragm opening makes out-of-focus elements appear more natural