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. 27-112mm when used with a Canon 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.
Note:
Not suitable for 35mm film SLR cameras or for any digital SLR camera with image sensor bigger than APS-C size, e.g. 1D series or Kodak Pro SLR/c.
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