The Pentax SMCP-DA* 50-135mm f/2.8 ED (IF) SDM Autofocus Lens is a high-quality telephoto zoom lens that is designed for exclusive use with Pentax digital SLR cameras. It offers a focal length that is equivalent (in 35mm format) from 75mm to 202mm. This wide coverage is ideal for a variety of telephoto applications, including portraiture, sports and scenery.
The image circle in DA-series lenses is designed to perfectly match the 23.5mm x 15.7mm size of the CCD used in Pentax digital SLRs to optimize camera performance.(*) This design also contributes to a drastic reduction in size, weight and production cost, compared to 35mm-format counterparts with similar specifications.
Pentax DA* (DA-Star) zoom lenses come equipped with the SDM System, which assures smoother, quieter auto-focusing operation by using a built-in ultrasonic motor. When mounted on the K10D digital SLR camera body, the focus mode is automatically switched to SDM-assisted auto-focusing. When mounted on older Pentax digital SLR camera bodies, the conventional autofocus mode using a camera-mounted motor is selected.
Like all Pentax lenses, this lens is treated with smc coating for maximum light transmission, sharp definition, and high contrast images. In addition, SP (Super Protective) coating made of a special fluoride compound has been applied to the front surface of the lens through the use of a unique evaporation process. As a result, the lens offers excellent water- and oil-repellent performance and makes for easier cleaning should the lens be accidentally smeared with fingerprints or cosmetics.