Early history

The company was founded as Asahi Kogaku Goshi Kausha in November 1919 by Kumao Kajiwara, at a shop in the Toshima suburb of Tokyo, and began producing spectacle lenses (which it still manufactures). In 1938 it changed its name to , and by this time it was also manufacturing camera/cine lenses. In the lead-up to World War II, Asahi Optical devoted much of its time to fulfilling military contracts for optical instruments. At the end of the war Asahi Optical was disbanded by the occupying powers, being allowed to re-form in 1948. The company resumed its pre-war activities, manufacturing binoculars and consumer camera lenses for Konishiroku and Chiyoda Kōgaku Seikō (later Konica and Minolta respectively).

Early 1950s to 2007

The period around 1950 marked the return of the Japanese photographic industry to the vigorous level of the early 1940s, and its emergence as a major exporter. The newly reborn industry had sold many of its cameras to the occupation forces (with hugely more disposable income than the Japanese) and they were well received. The Korean War saw a huge influx of journalists and photographers to the Far East, where they were impressed by lenses from companies such as Nikon and Canon for their Leica rangefinder cameras, and also by bodies by these and other companies to supplement and replace the Leica and Contax cameras they were using.

In 1952 Asahi Optical introduced its first camera, the Asahiflex (the first Japanese SLR using 35mm film). Since then the company has been primarily known for its photographic products. The company's photography products were imported to the United States from the 1950s until the mid 1970s by Honeywell Corporation and were labeled Honeywell Pentax rather than Asahi Pentax, the name by which they were distributed to the rest of the world. The company was renamed Pentax Corporation in 2002. It was one of the world's largest optical companies, producing still cameras, binoculars, and spectacle lenses as well as a variety of other optical instruments. In 2004 Pentax had about 6000 employees.

Merger with Hoya

In December 2006, Pentax started the process of merging with Hoya Corporation to form 'Hoya Pentax HD Corporation'. Hoya's primary goal was to strengthen its medical-related business by taking advantage of Pentax's technologies and expertise in the field of endoscopes, intraocular lenses, surgical loupes, biocompatible ceramics, etc. It was speculated that Pentax's camera business could be sold off after the merger. A stock swap was to be completed by October 1, 2007 but the process was called off on April 11, 2007. Pentax president Fumio Urano resigned over the matter, with Takashi Watanuki taking over as president of Pentax. However, despite Watanuki's previously stated opposition to a Hoya merger, on May 16 it was reported that Pentax had accepted "with conditions" a sweetened offer from Hoya, according to a source familiar with the matter. Pentax was under increasing pressure from its major shareholders, Sparx Asset Management in particular, to accept Hoya's bid.