The Sigma 17-70mm f/2.8-4.5 DC Macro lens is a large-aperture lens with a maximum f/stop of f/2.8 in wide angle setting. The super wide-angle capability of this zoom lens (equivalent range of approx. 25.5-105mm when used with a Pentax digital SLR camera) makes it ideal as an everyday large-aperture lens. In addition, the maximum magnification of 1:2.3 also enables close-up photography.

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.

Minimum focusing distance of 7.9" (20 cm) at all focal lengths

Correction for various types of aberration provided by one SLD (Special Low Dispersion) glass element and two aspherical lenses

The lens design incorporates an inner focusing system, which prevents the front of the lens rotating, making it particularly suitable for use with circular polarizing filters and petal shaped lens hoods

Zoom Lock Switch eliminates "Zoom Creep" during transportation