K-Mount Lens/Full-Frame Format Aperture Range: f/1.9 to f/22 High-Grade PENTAX HD Multi-Layer Coating 7 Elements in 6 Groups Super Protect SP Coating 8-Blade Round Diaphragm Lens Hood Included Pancake Form Factor Product features: High-grade lens with superb image rendition and beautiful texture While inheriting the design concept of the Limited series, this lens was designed through a series of mechanical and numerical evaluations, as well as human assessment of test-shooting samples, to deliver an image rendition unmatched by other models. The barrel, hood and cap are all made of high-grade aluminum, meticulously machined for an attractive appearance and beautiful texture. It also features a mount pointer with a shippoyaki (cloisonn) finish, which lets the user effortlessly and quickly mount the lens to a camera body. HD coating for exceptional image rendition This lens is treated with PENTAX-original HD coating.* Compared with conventional multi-layer coatings, this high-grade coating assures higher light transmittance and lower reflectance to deliver sharp, clear images free of flare and ghost images, even under such adverse lighting conditions as backlight. It elevates the imaging performance a further step up. * HD stands for High Definition. Round-shaped diaphragm for beautiful bokeh effect This lens features a completely round-shaped diaphragm, which produces a natural, beautiful bokeh (defocus) effect in the images captured, while optimizing the imaging performance of the distinctive Limited-series optics contained within. SP coating to repel dust and protect lens surface Applied to the front optical element, the PENTAX-developed SP (Super Protect) coating effectively repels water and grease to keep the lens surface free of dust, water and oily substances. This coating is also highly resistant to abrasion and scratches, keeping the lens scratch-free. Other features: The black model is marked with serial numbers starting with 0000001, while the silver model starts with 1000001. The lens also features an aperture ring to make best use of the range of functions featured in K-mount film-format cameras. Specifications: Focal Length: 43mm Equivalent to 66mm in 35mm format (when attached to PENTAX APS-C size DSLR cameras) Maximum Aperture: F1.9 Minimum Aperture: F22 Lens Construction: 7 elements in 6 groups Angle of View (Diagonal): 53(when attached to PENTAX 35mm full-frame SLR cameras) 36.5(when attached to PENTAX APS-C size DSLR cameras) Mount: KAF Minimum Focusing Distance: 0.45m (1.48 ft.