Designed for use with PENTAX K-mount DSLR cameras, the weather-resistant HD PENTAX-DA 55-300mm F4.5-6.3ED PLM WR RE telephoto zoom lens provides enhanced autofocus (AF) performance and outstanding optical performance in an ultra compact and lightweight package. It provides effective focal lengths between 84.5mm and 460mm when mounted on a PENTAX APS-C format DSLR. Its design enables quiet, high-speed AF operation in still-image shooting, as well as smooth and quiet AF tracking operation during video recording, with minimal noise created by focus and aperture shifts.