Unparalleled optical performance in a fast and steady telephoto zoom: In the pursuit to achieve the most outstanding image resolution in the 70-300mm class, Tamron's Anniversary lens - the SP AF70-300mm F4-5.6 Di VC USD (Model A005) - utilizes an advanced optical design that features an LD (Low Dispersion) and an XLD (Extra Low Dispersion) lens element made from specialized materials that prevent chromatic aberration. As a result, the SP AF70-300mm F4-5.6 Di VC USD (Model A005) boasts sharper contrast and greater descriptive performance than all others in its class. In addition, it is the first Tamron lens sporting a USD (Ultrasonic Silent Drive), Tamron's very own ultrasonic auto-focus drive mechanism. This USD mechanism delivers fast focusing, making it a perfect telephoto zoom choice for photographing sports, racing, or other fast-moving subjects. The lens also boasts Tamron's proprietary VC (Vibration Compensation) image stabilization to assist in hand-held photography, not only at long focal length ranges where blurring is common, but also under low-lit conditions, dramatically enhancing photographic freedom. This comnbination of best in class image resolution, Ultrasonic Silent Drive and Vibration Compensation is a new achievement of Tamron technology, culminating in the production of a premium 70-300mm telephoto zoom lens.