Tamron SP AF17-50mm F/2.8 XR Di II VC LD Aspherical [IF] is designed for exclusive use on digital cameras with smaller-size imagers and inherit all of the benefits of our Di products. These lenses are not designed for conventional cameras and digital cameras with image sensors larger than 24mm x 16mm. 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. The new 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. The new 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.) The new 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. ??