The Sigma 17-70mm F2.8-4 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 is equivalent to the angle of view of a 27-112mm lens in the 35mm format. It is 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) also 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. 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.