The Sigma 24-70mm f/2.8 IF EX DG HSM Lens is a large aperture standard zoom lens that's ideal for photojournalism and general professional photography. It provides (in 35mm terms) the equivalent of a 38-112mm f/2.8 lens upon current Pentax digital SLR cameras. The lens provides a bright viewfinder, speedy AF, and full-time manual focus override at any time without having to change the focusing switch position.
The Hyper Sonic Motor (HSM) ensures silent, high-speed AF function, and this is the first 24-70mm f/2.8 for Pentax cameras that can boast of this feature. The 24-70mm f/2.8 IF EX DG HSM features a Super Multi Layer Coating which reduces flare and ghosting. "DG" is a designation Sigma uses upon lenses featuring optical systems designed to meet the performance characteristics of digital SLR cameras.
- DG Lens Design
- DG Lens design corrects for various aberrations, with special coatings to improve color balance and reduce digital-sensor-based ghosting.
- HSM (Hyper Sonic Motor)
- Sigma's Hyper Sonic Motor provides smooth, silent AF with full-time manual focus override possible without needing to touch any switch.
- ELD & SLD Elements
- This lens uses three ELD (Extra-Low Dispersion) elements and two SLD (Special Low Dispersion) elements to correct chromatic aberration.
- 9-Blade Aperture
- The rounded 9-blade diaphragm opening makes out-of-focus elements appear more natural.