Tamron SP AF 17-50MM F/2.8 XR DI-II VC LD Aspherical (IF) Lens For Canon SLR Cameras

The Tamron SP AF17-50mm f/2.8 XR Di II LD Aspherical [IF] isa lightweight, compact, fast standard zoom lens designed exclusivelyfor digital SLR cameras. The focal length of this lens is equivalent toapprox. 26-78mm in 35mm format. This lens offers an f/2.8 maximum aperture throughout theentire zoom range, to ensure stress-free photographic shots at allfocal lengths and distances. Additionally, a broader through the use of faster shutter speeds as a result of themaximum aperture offers enhanced photographic pleasure. Note! Di-II lenses cannot be used with digital SLR cameras using imagesensors that are larger than that of an APS-C size imager, or with 35mmfilm SLR cameras. Optimized for Digital SLR The use of XR (Extra Refractive Index) glass optimizes the overall distribution of optical power, and also reduces various aberrations to the absolute minimum while achieving remarkable compactness. In addition, suitable positioning of two hybrid aspherical elements serves to maintain imaging performance and to shorten and compress the entire optical system. LD Glass An LD (Low Dispersion) glass element is used to accomplish effective compensation of on-axis and lateral chromatic aberrations, a critical factor for enhancing optical quality in digital photography, in order to achieve outstanding optical performance over the entire zoom range. Enhanced Peripheral Illumination Peripheral light fall-off is minimized when compared with that of conventional lenses for film cameras, so images are uniformly bright from the center to the periphery. Internal Surface Coating to Reduce Ghosting and Flare By employing Internal Surface Coatings (i.e., multiple-layer coatings on cemented surfaces of plural elements) and multiple-layer coating technology on ordinary elements, ghosting and flare due to the reflections that occur when light enters through the front element and reflections caused by the imagers themselves are reduced to the absolute minimum. Zoom Lock Mechanism The Zoom Lock prevents unwanted barrel extension when carrying the lens/camera combination.