The Sigma 18 mm - 200 mm HSM OS DC is a lens designed and produced by Sigma for Sony. It has been designed to work with SLR cameras. Since the first super zoom lens (18 mm - 125 mm D3.5-5.6 DC) in August 2004, Sigma has made several additions to this super zoom lens to make the user feel more comfortable and confident in outdoor photography. The common problem with long, slow zoom lenses are image blur that is caused by the shake of the camera. This Sigma lens eliminates that problem with its Optical Stabilization (OS) technology for Pentax. The Sigma 18 mm - 200 mm HSM OS DC also features an ultrasonic-type HyperSonic Motor (HSM). This Sigma lens features a complex optical design, with 18 elements in 13 groups. This includes one Super-Low Dispersion (SLD) glass element, and 3 elements to eliminate aberrations. This super zoom lens requires a minimum focus distance of 17.7 inches. The Optical Stabilization technology mentioned before has been designed to detect when the camera is panning and to automatically switch to operating in one axis only. The user will find this feature extremely useful when photographing moving items, i.e. sporting events. Other features of the Sigma 18 mm - 200 mm HSM OS DC include a focal length of 18 mm - 200 mm, an aperture range of f/3.5 - f/40 and a maximum magnification of 0.3x. The package comes complete with front and rear caps. The dimensions of this device are 3.1 inches by 3.5 inches and it weighs 21.2 oz. All these features make this device an ideal choice for users looking to add a great accessory to their photography arsenal.