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 when in wide angle setting. The super wide-angle capability of this zoom lens (equivalent range of approx. 25.5-105mm when used with a Nikon 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. This HSM version now incorporates the HSM feature, which gives this lens the capability to auto focus with all Nikon DSLR cameras (including the D40 and D40x). In addition, with the HSM (Hyper Sonic Motor) incorporated into this lens, focusing will be quieter and more responsive. 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 compatible with 35mm cameras or digital cameras using full-size image sensors (e.g. Kodak DCS14n or DCS PRO SLR/n).
Incorporation of the HSM feature allows it to autofocus with all Nikon DSLR 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