The 17-70mm F2.8-4 DC Macro HSM OS is the first lens in the category of Sigma's Global Vision. The Sigma 17-70mm F2.8-4 was designed to be the ideal all-purpose lens for APS-C sized sensors. With a great focal length and macro capability, the 17-70mm F2.8-4 is also equipped with a Hyper Sonic Motor (HSM) and an Optical Stabilizer (OS) for superior image quality. The HSM ensures quiet, accurate, and fast autofocusing while the OS compensates for camera shake when shooting by hand. The construction of the 17-70mm includes new TSC material (Thermally Stable Composite), which allows for increased durability as well a reduction in size by 30% compared to conventional models. Two FLD glass elements, which have performance equal to fluorite, are incorporated with one SLD element to reduce color aberration at the highest degree. The 17-70mm F2.8-4 Macro DC HSM OS is compatible with the Sigma USB dock for an increased level of customization. The perfect all-purpose travel lens, the 17-70mm F2.8 Macro DC HSM OS is a must have for any camera bag.