Designed exclusively for Nikon digital SLR cameras capable of wide- angle photography, the Sigma 10-20mm f/4-5.6 lens is a powerful tool for landscape photography and other wide-angle applications. The lens offers an ultra-wide angle of view of 94.5 to 56.8 degrees, with three special low dispersion (SLD) glass elements and three aspherical lenses providing optimum image quality throughout the entire zoom range. The lens also incorporates a Hyper Sonic Motor (HSM) to ensure quiet, high-speed autofocusing in addition to full-time manual focusing. Other features include a close focusing distance of 9.4 inches, a non-rotating lens barrel that perfectly suits the petal- shaped lens hood (included), and a one-year warranty. Specifications Focal length: 10-20mm Maximum aperture: f/4-5.6 Lens construction: 14 elements in 10 groups Angle of view: 94.5 to 56.8 degrees Number of diaphragm blades: 6 Minimum aperture: f/22 Minimum focusing distance: 9.4 inches Maximum magnification: 1:6.7 Mount: Nikon Filter size: 77mm Filter size: Petal-type hood Dimensions: 3.3 inches in diameter and 3.4 inches long Weight: 17.5 ounces Warranty: 1 year From the Manufacturer The 10 to 20 millimeters f4 to 5.6 EX DC HSM lens allows enjoyment of super wide-angle photography and it is a very powerful tool for indoor shooting and landscape photography with APS-C size image sensors of digital SLR cameras. Wide angle of view (102.4 degrees at 10 millimeters and 63.8 degrees at 20 millimeters) offers the photographer greater freedom of expression. Three SLD glass elements are employed for effective compensation of color aberration, which is a common problem with super-wide angle lenses. One piece of glass mold and two hybrid aspherical lenses, offer excellent correction for distortion, as well as all types of aberration. This lens is equipped with an inner focusing system, and the models which are equipped with HSM system provide quiet, high speed autofocus shooting and also offer full time manual focusing. It has a minimum focusing distance of 24 centimeters (9.4 inches) at all focal lengths. The non-rotating lens barrel perfectly suits the petal shaped lens hood. A circular polarizing filter can also be used conveniently. It covers a superwide angle of view 102.4 to 63.8 degrees Three pieces of Special Low Dispersion (SLD) elements and three aspherical lens elements produce top quality optical performance. Inner focusing system ensures the length of the lens remains unchanged whilst controlling aberrations. Equipped with HSM (Hyper Sonic Motor) system Minimum focusing distance of 24 centimeters (9.4 inches) at all focal lengths Relatively compact, lightweight for an ultra wide-angle zoom lensNote to customers: Vignetting will occur if the lens is used with digital cameras with image sensors larger than APS-C size or 35mm SLR cameras.