As a member of the EX series of lenses, this 3rd generation Sigma lens is designed with the highest level of optical technology and augments its predecessor with the addition of the Hyper-Sonic Motor (HSM) ensuring a quiet, high speed AF as well as full-time manual focusing capability. Housed in compact construction, the Sigma 24-70mm is a large aperture standard zoom lens ideal for all general photography including portraiture and landscapes. Physically, the shortest lens in the category, its overall length is 3.7 inches/94.7mm. With excellent optics, this could be the foremost performing lens in the category with stunning speed, clarity and color. Intricate lens construction includes Super Multi Layer Coating reducing flare and ghosting; the combination of ELD (Extraordinary Low Dispersion) and two SLD (Special Low Dispersion) glass elements and three Aspherical lenses provide excellent correction of all types of aberrations. Superior optical performance is ensured throughout the entire zoom range with the minimum focusing distance being 15in/38cm and maximum magnification ratio being 1:5.3. The rounded 9 blade diaphragm gives a natural look to backgrounds and foregrounds.