The super-wide angle’s useful range of view can be conveniently utilized by simply rotating the smooth zoom ring. SLD (Special Low Dispersion) Glass is used for effective compensation of color aberration. Two pieces of molded glass aspherical lens elements offer excellent correction for distortion as well as all types of aberration. It is an ideal lens for Digital SLR Cameras as well as film SLR cameras.HSM (Hyper Sonic Motor) provides quiet, high-speed autofocus shooting, as well as full-time manual focus. It is easy to revert to Manual Focus by simply turning the focusing ring and overriding the AF.An inner focus system provides high performance and convenience. The non-rotating lens barrel perfectly suits the matched petal shaped lens hood.
Sigma’s 17-35mm f2.8-4 EX combines a fast f2.8-4 maximum aperture with ultra wide angle zoom lens of 17-35mm. It incorporates aspherical lens elements in the front, as well as rear lens groups, to correct spherical aberration. It also incorporates internal focusing to prevent deterioration of the optical quality at close distances and to eliminate rotation of the front barrel during focusing. A “perfect hood” is provided. The AF drive for Sigma SA and Canon AF SLR cameras is equipped with a silent, responsive and fast Micro Hyper Sonic Motor (H.S.M.). The lens materials used in this new lens are lead and arsenic free ecological glass.
Tags: sigma, lense, canon lense, zoom, Canon, canon slr