The Sigma 28-70mm f/2.8 EX DG lens is a compact and lightweight constant f/2.8 aperture zoom lens that is optimized for digital SLR cameras, but can also be used with film SLR cameras. The 28-70mm zoom range makes this lens the ideal choice as a standard zoom lens for photojournalism or general photography.
The lens is specially optimized for digital SLR cameras, and the Super Multi Coating gives superb color performance while cutting down flare and ghost. Two SLD elements and four aspherical lenses provide the ultimate correction against distortion as well as all types of aberration, especially spherical aberration. Its advanced optical design ensures high performance throughout the entire zoom range.
Note: This lens (similar to Pentax "J" lenses) does not feature an aperture ring on the lens, and is not compatible with some of the older PZ series or with manual exposure cameras.