The Pentax SMC DA* 50-135mm F2.8 ED IF SDM  is an autofocus high-quality telephoto zoom lens. It 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.
Note! (*)Only compatible with Digital SLR cameras
Incorporates 3 Extra-low Dispersion (ED) glass lens elements to compensate for chromatic aberration.
DA*-series lenses feature tightly sealed, weather-resistant and dust-resistant construction that enhance durability for use in rain or dusty conditions.
Quick-Shift Focus System allows to instantly switch the focus mode from AF to manual with a slight twist of the focus ring.
SP (Super Protective) coating made of a special fluoride compound has been applied to the front surface of the lens to offer excellent water- and oil-repellent performance
Incorporates a metallic lens mount for extra durability
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 ultimate optical image quality. With aspherical elements, special optical-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
Quick Shift focusing
Super Protect coating
SDM focus motor