The Sigma 17-70mm f/2.8-4 DC Macro OS HSM Lens is a large-aperture lens with a maximum f/stop of f/2.8 in wide angle setting. The large zoom range of this 4x zoom lens (equivalent range of approx. 27-112mm when used with a Nikon digital SLR camera with an APS-C size chip) makes it ideal as an everyday large-aperture lens. In addition, the minimum focus distance of 8.7" along with the maximum magnification of 1:2.7 also makes the lens perfect for close-up photography.
Optical Stabilization (OS) anti-shake technology allows you to use shutter speeds approximately 4 stops slower than would otherwise be possible, without motion blur. This anti-shake technology, along with the fast f/2.8 to 4 aperture, makes this lens perfect for shooting in low light without a tripod.
The lens' Hyper Sonic Motor (HSM) ensures a quiet and high-speed auto focus, while its rounded, seven-blade diaphragm creates an attractive blur when shooting at wide apertures. The inner focusing system eliminates front lens rotation, making the lens particularly suitable for using the supplied petal-type lens hood and circular polarizing filters.
DC lenses are exclusively designed for digital SLR cameras with an APS-C size chip. The image circle (rear of lens) is made to match the smaller dimensions used for the image sensor on digital cameras. As a result these lenses are also more compact and lightweight, and are better matched to digital SLR cameras.