Designed exclusively for Nikon digital SLR cameras, the Sigma 18-200mm f/3.5-6.3 high-zoom-ratio lens covers a host of wide angle and telephoto focal lengths. The lens includes a built-in motor that provides high-speed autofocus, along with two special low dispersion (SLD) lenses and two aspherical glass elements that correct for all types of aberration. Sigma's super multilayer coating, meanwhile, reduces flare and ghosting and provides topnotch image quality throughout the zoom range. And thanks to the inner focusing system, you don't have to worry about front lens rotation, making this lens particularly suitable for petal lens hoods and circular polarizing filters. Other features include a minimum focusing distance of 17.7 inches, a maximum magnification ratio of 1:4.4, a compact and lightweight housing, and a zoom lock switch that prevents the lens from creeping due to its own weight.