1. Exceptional imaging performance made possible by the latest optical design technologies The lens incorporates one ED (Extra-low Dispersion) glass optical element and two Anomalous Dispersion glass optical elements to compensate for various aberrations and minimize the generation of the unwanted purple fringe effect. This is coupled with the high-grade, multi-layer HD (High Definition) Coating, which significantly reduces average reflectance in the visible ray spectrum to less than 50% compared to conventional models, and the innovative FREE (Fixed Rear Element Extension) focusing system. All together, these technologies effectively reduce the generation of flare and ghost images to a minimum over the entire focus range - from minimum focusing distance to infinity - and deliver clear, high-quality images. The lens also provides life-size magnification in close-range shooting to capture dramatic, fine-detailed close-up images. 2. Dustproof, weather-resistant AW construction for exceptional outdoor shooting reliability Ready for diverse outdoor shooting conditions, the lens features dustproof, weather-resistant AW (All Weather) construction for the first time in a PENTAX macro lens. This dependable construction prevents the intrusion of dust and moisture into the interior, using six sealing parts to optimize airtight performance. When mounted on a dustproof, weather-resistant PENTAX digital SLR camera body, it creates a highly dependable, durable imaging system that performs superbly in demanding shooting settings -such as snow, mist, rain, or in locations prone to splashing or spraying water. 3. Exclusive exterior design and outstanding operability The lens has an attractive, stylish appearance,with metallic exterior parts meticulously machined from high-grade aluminum. Its focus ring features the PENTAX-original Quick-Shift Focus System, which allows the photographer to instantly shift the focus mode from auto to manual after the subject has been captured in focus by the camera’s autofocus system. This single-action operation assures a smooth, comfortable focus-mode switching maneuver during manual-focus shooting, for dramatically improved operability. 4. Compact, lightweight design for superb maneuverability Despite the greatly improved imaging power made possible by the new optical design and outstanding AW construction, the lens is designed to be nearly as compact and lightweight as the smc PENTAX-D FA MACRO 100mm F2.8 WR (launched in December 2009), assuring outstanding maneuverability. 5. Other features ・A working distance of 5.1 inches (13 centimeters), at life-size magnification, to facilitate the shooting of unapproachable subjects, such as insects ・Individual serial number assigned to each lens: black models starting at 0000001, the silver model at 1000001 ・Circular diaphragm to produce a natural, beautiful bokeh (defocus) effect from open aperture to F5.6, while minimizing the streaking effect of point light sources ・SP（Super Protect）Coating applied to the front optical element, to keep the front surface free of dust or stains