The Sigma 24-70mm f/2.8 EX DG Macro DF lens has now been optimized to capture superior quality images even with digital cameras. DG is a designation Sigma uses on lenses featuring optical systems designed to meet the performance characteristics of digital SLR cameras.
Responding to the demands from professional photographers for a constant aperture zoom lens with a wider view, this lens covers focal lengths from 24mm ultra wide angle to 70mm medium telephoto with a bright viewfinder and easy AF/MF all the way through.
Three aspherical lens elements minimize spherical aberration, astigmatism and sagittal coma flare
Use of two SLD (Special Low Dispersion) elements results in excellent correction of chromatic aberration (the propensity of different colors of light to focus before and after the film plane)
DF (dual focus) mechanism is incorporated, making it easy to hold the lens during AF while providing a wide focus ring for easy manual focus
Non-rotating lens front allows the use of a flower shaped "Perfect Hood" and makes employing polarizing filters a snap