This new fast telephoto from Pentax is not only optically astounding but also supports the ultrasonic autofocus drive system for fast and quiet operation. Special optical glass including ED glass elements, aspherical lens elements and outstanding lens coating provide for excellent contrast characteristics, a consistent edge-to-edge sharpness and a particularly clear rendition of fine details. As well as the outstanding imaging attributes, PENTAX engineers have raised the mechanical characteristics of the lenses to a state-of-the-art level. Built-in ultrasonic motors (Supersonic Motors) in the lenses provide for extremely quiet and fast autofocusing. Both lenses are also weatherproofed and protected from penetrating dust by appropriate seals. The front lens elements of the lenses use the special Pentax SP - "Super Protect" - fluoride coating technology. This nano-technology protects the front lens against dust, finger marks or smearing, making the lenses exceptionally easy to clean. The Pentax "Quick Shift Focus System" allows the photographer to manually alter the focus point at will without having to take the camera out of the autofocus mode.
