Tamron's SP AF17-50mm F/2.8 XR Di II VC LD Aspherical (IF) is a high-speed, wide-to-moderate-telephoto zoom lens designed for Canon digital SLR cameras with smaller sensors. It covers the very popular 17-50mm focal length range (equivalent to 26-78mm in the full-frame 35mm format) making it extremely versatile. Tamron's Vibration Compensation (VC) mechanism minimizes the effects of handheld camera shake (up to 4-stops), providing a means to great low-light shooting. The lens delivers impressive sharpness and striking contrast over its entire focal length and aperture range. A maximum aperture of f/2.8 delivers images enhanced by shallow depth-of-field, and smooth, natural transitions in out-of-focus areas of the image.