The 70-200mm F2.8 EX DG Macro HSM II is one of Sigma's latest lenses, which was first announced in December 2007 for Canon, Nikon and Sigma, with a slew of follow-on releases adding compatibility for the remaining SLR mounts (i.e. Four Thirds, Sony and Pentax; however none of these versions are yet shipping). It's a successor to the 70-200mm F2.8 EX DG Macro HSM of February 2006, with a refined optical layout offering improved optical performance, and becomes the fourth iteration of the same basic EX design first unveiled in 1999 (which was itself preceded by a well-respected 70-210mm F2.8 for 35mm). The HyperSonic Motor (HSM) focusing system promises fast, silent and accurate autofocus for users of all brands of DSLR, although Pentax users should be aware that this lens is effectively of 'KAF-3' mount specification, and therefore won't focus on bodies which don't support SDM lenses. Aside from that specific incompatibility, this is a design which will work on almost every DSLR ever made, and is therefore of unusually broad buyer appeal.