The Sigma 8-16mm F4.5-5.6 DC HSM is the only one of its kind. This is the first ultra wide zoom lens with a minimum focal length of 8mm, designed specifically for APS-C size image sensors. It has an equivalent angle of view of a 12-24mm lens when used on digital camera with an APS-C size image sensor. Sigma's new FLD glass elements, which have the performance equal to fluorite glass, compensate for color aberration. One hybrid aspherical lens and two glass mold elements give excellent correction for distortion and astigmatism. An inner focusing system produces high definition images throughout the entire zoom range and the Super Multi-Layer Coating reduces flare and ghosting while superior peripheral brightness ensures high contrast images throughout the entire zoom range. HSM ensures quiet and high speed AF as well as full-time manual focus capability. It has a minimum focusing distance of 9.4 inches throughout the entire zoom range which allows photographers to emphasize the subject by creating exaggerated perspectives. This lens has a compact construction with an overall length of 4.2 inches and a maximum diameter of 2.9 inches and is perfect for shooting landscape photography, architecture, building interiors, photojournalism, wedding photography, group pictures and more. Please Note Vignetting will occur if the lens is used with digital cameras with image sensors larger than APS-C size or 35mm SLR cameras.