Sigma 18-200mm f/3.5-6.3 DC OS HSM

The Sigma 18-200mm f/3.5-6.3 DC OS HSM is the latest in the company's long line of superzooms, which stretches back to the early 1990s and a series of 28-200mm (and later 28-300mm) lenses for 35mm SLRs. In fact Sigma was the first company to produce a superzoom for the burgeoning budget DSLR market, with its 18-125mm D3.5-5.6 DC of August 2004, followed shortly after by an 18-200mm F3.5-6.3 DC in February 2005. However the big problem with long, slow zooms is image blur due to camera shake, and in March 2007 Sigma duly announced this new version of the 18-200mm with the addition of 'Optical Stabilization' (OS) technology for Canon, Nikon and its own SD range of DSLRs (Sony and Pentax users, of course, benefit from sensor-shift image stabilization of all lenses). In somewhat curious fashion, the Nikon mount version also sports an ultrasonic-type 'HyperSonic Motor' (giving rise to the HSM tag,) while the Canon and Sigma mount models use a conventional micro-motor for focusing.