The Sigma 28-70mm f/2.8-4 DG zoom lens offers a wide f/2.8 aperture at 28mm, and is very lightweight (just 8.6 oz) and compact (only 2.4 inches long). The size and weight of this standard lens makes it very suitable for landscape photography, and snapshots.
DG is a designation Sigma uses on lenses featuring optical systems designed to meet the performance characteristics of digital SLR cameras.
Note:
AF not supported by D40 and D60 cameras.
Incorporates an Aspherical lens element to minimize distortion
As part of the DG line, this lens is optimized for digital cameras