"The HD Pentax-D FA 150-450mm F4.5-5.6 ED DC AW super-telephoto zoom lens is designed for use with Pentax K-mount digital SLR cameras. It has been developed to cover focal lengths from 150mm to 450mm - a focal-length range most demanded by high-end Pentax -camera users. It features the Pentax -original, high-grade HD Coating to produce extra-sharp, high-contrast images even under demanding lighting conditions such as in backlight. It also incorporates three ED (Extra-low Dispersion) glass elements and a super-low dispersion glass element to effectively compensate chromatic aberration. Its dustproof, weather-resistant body also makes it extremely dependable and durable in demanding outdoor conditions. Super-telephoto coverage with three-times zoom ratio When mounted on a PETAX K-mount SLR camera body, this zoom lens covers a super-telephoto range from approximately 230mm to 690mm in the 35mm format. It is designed to be compact and light enough to handhold during long-range shooting of such subjects as wildlife, aircraft and sports. Outstanding image description Thanks to its state-of-the-art optics featuring three ED (Extra-low Dispersion) glass elements and one superlow dispersion glass element, this zoom lens effectively minimizes spherical and chromatic aberrations, while producing crisp, high-quality images free of color bleeding. Its MTF (Modulation Transfer Function) curve is programmed to be higher than those of conventional models|230mm-690mm Focal Range on APS-C|Super Telephoto Zoom Lens|New Auto Focus Preset Button|9 Rounded Aperture Diaphragm Blades|All Weather Construction|High performance Optical Design with HD coating"