Pentax 35mm f/2.0 SMC FA AL

HD Coating is a new-generation, multi-layer lens-coating technology, developed to provide better-quality optical characteristics in a greater number of lens products. It was designed to satisfy the demand for higher lens performance that is required due to advances in digital cameras.With the application of a state-of-the-art multi-coating process... morecompletely different from the conventional one, HD Coating provides a coating layer thickness and anti-reflection performance that is close to theoretical design specifications. A lens surface treated with HD Coating assures reflectance that is less than 50% that of conventional multi-layer coatings.The graphs above show the optical performance of samples selected from each category, after treatment with 10 layer-forming processes. As you can see, HD Coating samples show extremely high layer-forming precision and extremely low discrepancy in reflectance. Since reflectance curves are almost identical at different wavelengths, the HD Coating graph demonstrates optical characteristics which deliver ideal color balance.The History Of Pentax Lens Coating Technology:- A pioneer of multi-layer lens coating technology: In 1971, PENTAX made an innovative advancement in optical technology by increasing the number of coating layers from two — the norm at the time — to as many as seven.- Since then, lenses with the prefix smc PENTAX have been preferred by many photo enthusiasts. With the advancement of production technologies and camera digitalization, PENTAX's multi-layer coating technology has continued to evolve to meet the demands of the times.Development Of Aero Bright Coating Boasting The Highest Anti-reflection Performance:- PENTAX later developed Aero Bright Coating, which provided excellent transmissivity through a wider range of wavelengths and outstanding anti-reflection performance, by applying a silica aerogel coating layer with a uniform porous structure over a regular multi-coating.- Aero Bright Coating was first introduced in 2009 to the smc PENTAX-DA 55mm F1.4 SDM, and helped to further improve the optical characteristics of high-performance lenses.The Birth Of Higher-performance, More Cost-efficient Hd Coating:- Even though Aero Bright Coating had superior anti-reflection performance, its nano-order, porous structure has a very delicate coating structure that can be easily damaged by abrasions or scratches. Because of this, its application was limited to a small selection of lens surfaces. It also wasn't suited for mass production because of restrictions faced in the production process. It therefore could be applied only to rather high-priced models.- To resolve this setback, PENTAX set out to further upgrade its multi-layer coating technology — something indispensable in optical glass — and achieve an optical performance close to that of Aero Bright Coating. Compared with a conventional seven-layer coating applied by a vacuum evaporation process, the new HD Coating forms an eight-layer