Ring USM, high-speed CPU, and image optimized AF algorithms for fast auto focusing. Optimized lens coatings for exceptional Color balance and minimal ghosting, florine coating on front and rear lens surfaces to reduce smears and fingerprints. New optical design utilizes 1 Super UD lens element and 2 UD lens elements to minimize chromatic aberration in the outer area at wide- angle; as well as eliminates color blurring around the edges of the subject, for images with high resolution and contrast. Combines 2 types of aspherical lenses to reduce spherical aberration, and achieve high image quality across the entire screen area and throughout the full zoom range. Zoom lock lever locks the zoom position at the wide end for safe transporting