The PENTAX DA * 50-135mm F2.8 ED (IF) telephoto zoom lens is designed for exclusive use with PENTAX digital SLR cameras, delivering the highest level of optical image quality. With aspherical elements, special extra-low dispersion glass elements and original lens coatings, this lens is superior in terms of contrast, clarity and edge-to-edge sharpness. The 50-135mm features tightly sealed, weather-resistant and dust-resistant construction to enhance durability for use in rain or dusty conditions. A new SDM system has been incorporated for smoother, quieter autofocusing operation using a built-in supersonic motor. It also features the PENTAX-original Quick-Shift Focus System for instant switching to manual-focus operation and PENTAX-original SP (Super Protect) coating to repel dust, water and grease.