Tamron's SP AF17-50mm F/2.8 XR Di II VC LD Aspherical [IF] (Model B005) is a high speed f/2.8 wide-to-moderate-telephoto zoom lens designed exclusively for Canon and Nikon-mount digital SLR cameras with smaller sensors and now features Tamron's proprietary tri-axial Vibration Compensation (VC) mechanism that minimizes the effects of handheld camera shake. This SP 17-50mm F/2.8 XR Di II VC covers the very popular 17-50mm focal length range (equivalent to 26-78mm in the full-frame 35mm format) making it extremely versatile. Its wide aperture and outstanding performance provide practical advantages in low-light shooting and aesthetic image control, thereby enriching the user's range of creative expression. This lens delivers impressive sharpness and striking contrast over its entire focal-length and aperture range, and at its maximum aperture of f/2.8 it produces beautiful images enhanced by shallow depth of- field, and smooth, natural transitions in out-of-focus areas of the image (i.e. excellent bokeh.) This lens is equipped with Tamron's proprietary Vibration Compensation (VC) image stabilization mechanism, which controls the effects of camera shake in three planes. VC provides more opportunities for sharp hand-held photography (up to 4-stops) at the slow shutter speeds needed when shooting in low-light conditions (e.g. night or indoor scenes) dramatically enhancing the user's level of photographic freedom.