Sigma Zoom Wide Angle-Telephoto 18-200mm f/3.5-6.3 DC Autofocus Lens for Canon Digital EOS

This lens design incorporates aspherical lenses and SLD (Special Low Dispersion) glass that provides the utmost correction for all types of aberrations and enables this extended superzoom lens to be housed in a compact and lightweight construction of 70mm (2.8 ) in diameter, 75.6mm (3 ) in length and weighing just 385g/13.5oz. Superb image quality The power layout of this lens is exclusively designed to suit the characteristics of digital SLR cameras. Two SLD glass elements and two hybrid aspherical lenses offer outstanding correction of various aberrations and produce high-quality images. SLD glass is especially effective in the compensation of longitudinal chromatic aberration, usually evident in tele-photography, and magnified chromatic aberration caused by wide-angle photography. Aspherical lenses offer excellent correction of spherical aberration and astigmatism. Minimal vignetting and superior peripheral brightness is ensured. Super multi layer coating The advanced optical design is optimized for digital SLR cameras. In addition, the Super Multi Layer coating on each glass surface produces superb color rendition, while reducing flare and ghosting. Inner focusing system The lens design incorporates an inner focusing system, which prevents the front of the lens rotating, making it particularly suitable for use with circular polarizing filters and petal shaped lens hoods. The overall length of the lens does not change during focusing, ensuring convenient handling and ease of use. Zoom lock switch A zoom lock switch eliminates zoom creep during transportation, a convenient feature when traveling. Magnification scale A magnification scale is displayed on the lens barrel for each focal length, ensuring ease of use.&ref=Become