Sigma 17-35mm f/2.8-4 EX DG IF HSM Aspherical Super Wide Angle Zoom Lens for Sigma SLR Cameras

17-35mm F2.8-4 EX DG ASPHERICAL HSM is specially designed to suit the characteristics of digital SLR cameras. This lens has a compact dimensions that features overall length of 86.2mm/3.3in. SLD (Special Low Dispersion) Glass is used for effective compensation of color aberration. Two pieces of molded glass aspherical lens elements offer excellent correction for distortion as well as all types of aberration. Excellent optical performance was realized both for Digital SLR cameras and film SLR cameras.It has a minimum focusing distance of 27cm / 10.6in. at all focal lengths, and maximum magnification ratio of 1: 4.5. This super-wide angle lens' useful range of view is very convenient for close-up photography.Sigma, Nikon and Canon are equipped with Hyper Sonic Motor (HSM). It is easy to revert to Manual Focus by simply turning the focusing ring and overriding the AF.An inner focus system provides high performance and convenience. The inner focus system allows the lens to be focused without having to rotate the front of the lens, so the lens accepts a Petal-type hood and it is also easy to use a circular polarizing filter.An inner focus system provides high performance and convenience. The non-rotating lens barrel perfectly suits the matched petal shaped lens hood.