Amazon.com Product Description
Sigma's 17-70mm DC macro lens is an ideal large-aperture standard zoom lens for Nikon digital SLR cameras with APS-C size image sensors, making it suitable for a wide variety of subjects. The lens offers a minimum focusing distance of 7.9 inches throughout the entire zoom range, along with a maximum magnification of 1:2.3 for close-up macro photography. The new lens design and multilayer lens coating, meanwhile, reduce flare and ghosting--a common problem with many digital cameras. Add in a Special Low Dispersion (SLD) glass element and two aspherical lens elements and you have a lens that can correct all types of aberrations while producing a high level of optical performance at every interval.
The lens also offers a large aperture of F2.8 at the 17mm wide-angle setting, yet is notably compact, with an overall length of 3.2 inches and a diameter of 3.1 inches. Plus, it performs superbly even in relatively low-light conditions, such as indoors or at dusk. Users will also appreciate the inner focusing system, which provides a fast autofocus speed while preventing the front of the lens from rotating, making it particularly suitable for use with circular polarizing filters and petal-shaped lens hoods. Also equipped with a zoom lock switch that eliminates "zoom creep" during transport, the lens weighs 16 ounces and carries a one-year warranty.