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is a wholly owned division and brand name of Hoya Corporation. It succeeds to the business operations of , which was merged with and into Hoya on March 31, 2008.


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). 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.

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. On August 6, 2007, Hoya completed a friendly public tender offer for Pentax and acquired 90.59% of the company. On August 14, 2007, the company became a consolidated subsidiary of Hoya. On October 29, 2007, Hoya and Pentax announced that Pentax, as the company ceasing to exist, will merge with and into Hoya effective on March 31, 2008. Hoya will retain the Pentax brand name.


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. This was the background to the development of Asahi Optical's first camera.

The Screw mount cameras

The Asahiflex Series

Asahi Optical introduced its first 35 mm camera in 1952. Asahi was unusual in deciding to start with a high-quality 35mm camera that was not a copy of something else. Its designers were convinced of the inherent superiority of the SLR and so proceeded along these lines. This effort resulted in the Asahiflex I, which was also the first Japanese 35mm SLR.

The Asahiflex I had a non-interchangeable waist-level viewfinder, with a direct optical viewfinder for eye-level use. The Asahiflex I had a non-returning mirror and shutter speeds from 1/25 to 1/500. The camera used the M37 screw mount. It went through some minor modifications for flash use, resulting in the IA. With the IIB a key advance was made: the quick-return mirror. The problem of mirror black-out was one of the main problems with prior SLR designs, greatly reducing usability and a major reason for the greater popularity of the rangefinder. With the IIB there emerged the first practical quick-return mirror, a vital innovation and one which was quickly adopted by other manufacturers. With the final model in the series, the IIA, the Asahiflex gained slow speeds from 1/25th of a second to 1/2 of a second.

  • Asahiflex I (1952 – 1953)
  • Asahiflex IA (1953 – 1954)
  • Asahiflex IIB (1954 – 1956)
  • Asahiflex IIA (1955 – 1957)

Asahi-Pentax Series (pre Spotmatic)

The Asahiflex was an excellent camera, but the market demanded more. The last drawback of the Asahiflex was that the camera lacked a pentaprism; it was very difficult to use the camera in a vertical position and taking pictures of moving objects was almost impossible. The small viewfinder on top of the camera was of little use when the photographer wanted to use a 135 mm or 500 mm lens. The problem was recognized by Asahi, and in 1957 Asahi Optical's first SLR in its modern form was introduced.

The Asahi Pentax is widely recognised as one of the pivotal SLR designs of the 20th century. The form and layout of the Asahi Pentax (often referred to by collectors as the 'AP') exerted tremendous influence over the next 30 years of SLR design. The AP was not necessarily technologically innovative: most of the technologies present had already been developed. What the AP represented, however, was the first time that the best SLR technologies of the time had been brought together in one compact package. As well as the inherent advantages of the SLR design, the AP incorporated instant mirror return, a hinged film back for easy loading and the now firmly established rapid thumb-wind advance on the right of the camera. Compared with the cameras of the time, the AP represented a breakthrough in convenience and usability. The AP dropped the M37 mount and instead utilised the M42 screw mount, first introduced with the German Contax S in 1949. The Asahi Optical lenses bore the 'Takumar' name and quickly gained a high reputation.

There is some confusion about the etymology of the name, some sources claim it was licensed from VEB Zeiss Ikon, and derived from the combination "PENTAprism" and "contaX". The explanation on does not mention Contax or Zeiss Ikon, and states that the name was formed from "PENTAprism" and "refleX", being the reflex mirror of an SLR camera. A third variation substitutes "Asahiflex" for "reflex", which is at least logical as the Asahiflex cameras had waist-level viewfinders and therefore the pentaprism of the Asahi Pentax would have been a significant differentiating feature.

The AP went through various iterations until 1964. Each successive model incorporated minor improvements, the most noticeable being the incorporation of the two shutter speed dials (one for high speeds and one for low speeds) into one. The AP of 1957 is externally almost identical to the 1964 SV.

Spotmatic Series

However, by the 1960s the clamour for in-camera exposure metering was rising. It was possible to attach an external CdS (Cadmium sulfide) exposure meter to the later AP-derived models, but in 1960 the next breakthrough arrived. At the 1960 Photokina camera show, Asahi exhibited the Spot-matic prototype. This camera took exposure measurements, via a spotmeter, through the taking lens, an incredible innovation. The camera excited tremendous attention and in 1964 the first production Spotmatic (hyphen dropped) emerged. The Spotmatic was virtually identical to the prototype; however, the spotmeter was replaced with an all-over average-reading exposure meter in order to give more consistent results. The camera was an instant success and was snapped up by the thousands, although Asahi had been beaten into production by the Topcon RE Super which went on sale in April 1963; the Topcon failed to attract the same degree of commercial success.

In 1966 Asahi Optical had produced one million SLR cameras since the first Asahiflex of 1952. It took them only another three years, until 1969, to reach two million. This period was a time of complete pre-eminence for Asahi Optical. During the Spotmatic era Asahi were manufacturing more SLRs per month than all the other camera manufacturers combined. One of the technological highlights was the Electro-Spotmatic of 1971. This camera was one of the very first to incorporate automatic exposure. The series concluded in 1973 with the introduction of the Spotmatic F (now incorporating open-aperture metering rather than the stop-down metering of the early models).

However by the mid-1970s the limitations of the M42 mount were being felt. By this time most other manufacturers had opted for a bayonet lens mount. It was a great step for Asahi Optical to take but the M42 screw mount, by now widely known as 'Pentax screw mount', had reached the end of its useful life. Pentax were now to adopt the lens mount that would see them through the next 30 years.

Other Prototypes

In 1960, the same year that Asahi Optical introduced the Spot-matic prototype at Photokina, they also showed another SLR prototype which they called the Metalica. The Metalica gave a glimpse into the future direction of Pentax cameras; it featured a prototype bayonet lens mount, a vertical-traveling, metallic Copal-type focal plane shutter (from which the camera drew its name), and an already obsolescent coupled selenium light meter. The light meter was not TTL, but instead featured the typical large selenium mini-lens pattern on the front of the pentaprism. Otherwise the camera resembled the Spot-matic in appearance. While Asahi Optical didn't put the Metalica into production, the concepts of a bayonet lens mount and a metal focal plane shutter were already being discussed internally at the company.

In 1966 Asahi Optical showed a revised prototype of the Metalica named the Metalica II. Gone was the cumbersome selenium light meter, replaced with a now standard internal CdS meter. The Metalica II retained the bayonet lens mount shown in the earlier 1960 prototype, and also featured an improved Copal-square metallic shutter. But the biggest innovation was the fully automatic shutter operation coupled to the TTL meter. The metering system, for the first time in a 35mm SLR, controlled the shutter speed automatically based on the aperture set. With these innovative developments, the Metalica II pioneered features that would not surface on Pentax production cameras until the Electro-Spotmatic (ES) (automatic aperture-priority exposure) in 1971 and K2 (vertical metal shutter, bayonet lens mount, automatic aperture-priority exposure) in 1975. (Cecchi 1991:80-86)

K Mount cameras

K Series

  • K2 (1975 – 1980)
  • KX (1975 – 1977)
  • KM (1975 – 1977)
  • K1000 (1976 – 1997)

Three new models were introduced at once in 1975: the K2, KM and KX. The KM was almost identical in features and operation to the Spotmatic F. The KX featured a better TTL light meter using SPD (silicon photodiodes), visible aperture and shutter speeds in the viewfinder, and a mirror lock-up mechanism. The K2, the flagship model, incorporated aperture-priority autoexposure with a fully manually selectable range of shutter speeds from 1s to 1/1000. The only other aperture priority camera Pentax had made up to this point, the ES series, only had manual shutter speeds from 1/60 upwards. A special version of the K2 was also produced (called the K2DMD) to use a motor drive and data back. A later addition to the K series was the K1000 (basically a KM stripped of its self-timer and depth of field preview), later to find fame as the perennial camera of choice for photography students.

What set these cameras apart from any earlier Pentax was the removal of the M42 lens mount. With the K series of cameras, Pentax followed its rivals and introduced its own bayonet mount, the K mount. Still the basis for Pentax lenses and cameras today, this offered greater convenience and enabled the production of faster lenses such as the 50 mm . Eager to keep M42 users in the Pentax system, an M42-K Mount adaptor was offered, enabling M42 users to continue to use their existing lenses (with loss of automation).

The K series cameras followed the design ethos of the time, big and heavy. But scarcely had the K series been introduced, than Pentax began working on a new camera line, a new camera line reflecting a new ethos - one which continues to influence Pentax to this day.

M Series

The M series cameras were noted for their compact size, among the smallest and lightest 35 mm SLRs ever made. Except for the MX, all were based on the same basic camera body, and featured aperture-priority exposure automation. While superficially resembling the ME, the MX was designed as a manual-only SLR system targeted to the advanced amateur or professional photographer, and had its own set of accessories that were mostly incompatible with the other M series cameras. Conversely, the other M-series cameras were targeted squarely at casual users. None of the M-series, with the exception of the MX, featured a depth of field preview.

The ME featured aperture-priorty only automation with no manual override. The MX was entirely manual and resembled the earlier KX in features. The ME Super was an ME with a manual mode. The MG, MV, and MV1 were even simpler versions of the original ME.

The ME-F was an early attempt at an autofocus SLR using a special 35-70mm zoom with a motor built into the lens.

  • ME-F (1981 – 1988)
  • ME (1976 – 1980)
  • ME Super (1980 – 1987)
  • MG (1982 – 1985)
  • MV (1979 – 1982)
  • MV1 (1979 – 1982)
  • MX (1976 – 1985)

A Series

The A series added fully-programmed exposure control (adjusting both aperture and shutter speed automatically) to the M series. To enable control of the lens aperture by the camera body, it used the new KA-mount, a backward-compatible modification that also allowed the array of standard K-mount lenses to be used in manual and aperture-priority exposure modes. The A series were the first cameras from Pentax to use LCD digital displays for exposure information in the viewfinder. The super A / super PROGRAM and the program A / program PLUS both used a translucent white window on the front of the pentaprism to provide backlight to the LCD display without having to use the battery for illumination.

  • super A / super PROGRAM (1983 – 1987)
  • program A / program PLUS (1984 – 1988)
  • A3/A3000 (1985 – 1987)


The LX model was a tough, professional-grade competitor to the Nikon F3, the Canon F1, Olympus OM's, and Contax RTS. Like the Nikon F3 and Canon F1 it was very rugged and had interchangeable screens and viewfinders. Yet it was smaller and lighter, better sealed against the weather, and with its S69 screen had a brighter viewfinder than almost any camera ever made . The LX used an advanced metering system that measured the light falling on the first shutter curtain during exposure (as opposed to most cameras which measure light at the viewing screen). During long exposures the LX actually measured light reflected from the film itself. Because of this metering system, the LX could perform very accurate long exposures.

Shutter speeds and apertures were visible in the viewfinder in an arrangement similar to the earlier KX. The camera remained in production for more than 20 years.

  • LX (1980 – 2001)

P Series

  • P5/P50 (1986 – 1989)
  • P3/P30 (1985 – 1988)
  • P3n/P30n (1988 – 1990)
  • P30t (1990 – 1997)

SF Series

The SFX (called the SF1 in the US) was the world's first AF SLR with built-in TTL auto flash, which is retractable. Pentax has referred to the built-in flash as "RTF" (Retractable TTL Flash) ever since then.

  • SFX/SF1 (1987 – 1989)
  • SFXn/SF1n (1989 – 1993)
  • SF7/SF10 (1988 – 1993)

Z/Pz Series

  • PZ-10 (1991)
  • PZ-1 (1991)
  • PZ-20 (1992)
  • PZ-50 (1992)
  • PZ-1P (1994)
  • PZ-70 (1995)

MZ/ZX Series

Cameras known as MZ models elsewhere were named ZX models in the USA, the MZ5 being known as the ZX5 in the USA. The exception to this rule was the MZ6 which was known as the ZXL in the USA. Models shown on the same row are model replacements/upgrades in the range, so the MZ10 was replaced by the MZ7 which was subsequently replaced by the MZ6/ZXL. All were compact SLRs and included autofocus KAF lens mount and built in RTF except the MZM.

Models which were also backward compatible with both the KA and K mounts.
MZ5 MZ5n
MZM (manual focus version of MZ5 with no built in flash) Pentax KA lens mount.

Models which were backward compatible with the KA mount but not the K mount.
MZ50 MZ30

*ist Series (Film)

*ist (2003 – 2006)


MZ-D Prototype

The Pentax MZ-D, also known by its internal code name of MR-52, was a prototype digital single-lens reflex camera. It was announced at Photokina in September 2000 and was demonstrated to the press at the Photo Marketing Association (PMA) show in January 2001. In October 2003, Pentax canceled the camera, stating "The cost of manufacturing the prototype SLR 6-megapixel digital camera meant it was not a viable product for our target market."

*ist Series (Digital)

In 2003 Pentax released their first Digital SLR, the Pentax *ist D which uses a 6 megapixel CCD. What set Pentax D and DS DSLRs apart from the competition was the clarity and high magnification provided by their pentaprism viewfinders, a very useful feature considering the support for legacy manual focus lenses. In 2004 Pentax released the Pentax *ist DS, its first real consumer model (retailing under $1000 USD). In 2005 Pentax released the Pentax *ist DL, a model with fewer features than the DS and a lower price. All Pentax's digital SLRs are compatible with K-mount lenses, and M42 (42 mm screw mount) lenses (with adaptor). Due to the smaller size of the CCD, lenses have an effective field of view of 1.5 × times the same lens in 35 mm format. So, where a 50 mm lens was considered a "normal" lens on 35 mm film, that same lens on a 1.5× "crop factor" camera has the field of view of a 75 mm lens on film. This only uses the center of the lens' projected image. To address this "crop factor," Pentax created a new series of lenses that were designed only to cover the smaller sensor. These are the DA and D-FA models of new lenses for their digital SLRs, which still feature the K-mount but have a smaller back-focus element designed specifically for use with the Digital SLR lineup.

  • *ist D (2003 – 2006)
  • *ist DS (2004 – 2006)
  • *ist DS2 (2005 – 2006)
  • *ist DL (2005 – 2006)
  • *ist DL2 (2006)

K Series (Digital)

In May 2006, Pentax announced a new line of Digital SLR cameras, based on the *ist D series. The K100D and K110D combine the features of the *ist DL2 and DS2, while incorporating in-body shake reduction in the K100D model. The Pentax K10D, a low-priced 10-megapixel weatherproofed model, was announced on 14 September 2006.

The K10D features a pentaprism viewfinder (instead of the slightly dimmer pentamirror on some previous models), full programmed, aperture and shutter priority modes, and a new mode called Sensitivity-priority where the rear dial adjusts light sensitivity and the camera adjusts shutter speed and aperture to maintain correct exposure. In addition, the K10D can write JPEGs and two versions of RAW files (PEF, and the new Adobe standard DNG).

The K100D Super is a slight upgrade to the K100D announced in June 2007. The upgrade includes features from the K10D, such as an improved SR system, a dust removal system, and power contacts that allow the use of Pentax's SDM ultrasonic focusing technology recently introduced with the DA* lens line. The power contacts also provide the power zoom function that Pentax introduced in the 1990s.

On January 23, 2008, Pentax announced the K20D and K200D, which replaced the K10D and K100D series respectively. The K20D features a 14.6 megapixel CMOS APS-C sized sensor (the highest-resolution sensor in that format as of January 2008), a special 21 fps burst mode, live preview on the LCD display, and an increased sensitivity range extending to ISO 6400. The K200D adopts the 10 megapixel sensor and weather sealing of the K10D, among other improvements, while retaining the smaller body size of the K100D Super.

Optio (Digital)

Pentax Optio A40 is the flagship of the Optio line, with a 12 MP 1/1.8" image sensor, a three times zoom lens, a 2.5" LCD display screen, and in-body SR similar to that used on Pentax DSLR models.

Pentax Optio A30 has a 10 MP 1/1.8" image sensor, a three times zoom lens, a 2.5" LCD display screen, and in-body SR similar to that used on Pentax DSLR models.

Pentax Optio V10 has an 8 MP image sensor, a three times zoom lens, and a 3" LCD display screen.

Pentax Optio S10 has a 10 MP image sensor, a three times zoom lens, a 2.5" LCD display screen, and is DivX certified.

Pentax Optio Z10 has an 8 MP image sensor, an internally zooming seven times zoom lens, a 2.5" LCD display screen, and in-body SR similar to that used on Pentax DSLR models.

Pentax Optio M40 has an 8 MP image sensor, a three times zoom lens, and a 2.5" LCD display screen.

Pentax Optio E40 has an 8 MP image sensor, a three times zoom lens, a 2.4" LCD display screen, and supports standard AA batteries.

Pentax Optio W10 has a 6 MP image sensor, an internally zooming three times zoom lens, 2.5" LCD display screen, and is waterproof - 30 minutes of continuous operation at an underwater depth up to five feet, and dustproof (Class 5 dustproof performance of category 2).

Pentax Optio WPi has a 6 MP image sensor, an internally zooming three times zoom lens, 2" low-reflection LCD display screen, and is waterproof (JIS Class 8 water resistant rating). Continuous underwater picture-taking possible for 30 minutes at a depth of 1.5m to ten feet for up to 2.5 hours at a time.

Pentax Optio W30 has a 7 MP image sensor, an internally zooming three times zoom lens, 2.5" LCD display screen, and is waterproof to ten feet for up to 2.5 hours at a time.

Other formats

Pentax is one of the few camera manufacturers still producing medium format cameras. At the time of writing, there are two offerings, one in the 6×7 cm format (Pentax 67 II) and one in the 6×4.5 cm format (Pentax 645NII). Both use the 120 film format, which is a roll film. These cameras build on the Pentax SLR design experience. The shape of the Pentax 67 is broadly similar to a 35 mm SLR camera. By contrast, the Pentax 645 resembles other medium-format cameras by makers such as Mamiya and Bronica, which tend to be cube-shaped.

Another interesting product was the tiny Auto 110 reflex system, based on the 110 pocket-instamatic film format.

Corporate cooperation and competition

In 2005, Pentax Corporation partnered with Samsung Techwin to share work on camera technologies and recapture market ground from Nikon and Canon. Then Pentax and Samsung started releasing new DSLR siblings from this agreement. The Pentax *istDS2 and *istDL2 also appeared as the Samsung GX-1S and GX-1L, while the jointly developed (90% Pentax and 10% Samsung) Pentax K10D gave birth to the Samsung GX-10. Pentax lenses (made in Vietnam) are also rebranded and sold as the Schneider Kreuznach D-Xenon and D-Xenogon lenses for the Samsung DSLRs.

On December 21, 2006, Hoya Corporation and Pentax Corporation held a joint press conference announcing their merging into Hoya Pentax HD Corporation, to become fully effective on October 1st, 2007. Despite turmoil within Pentax that occurred following this announcement, including the resignation of Pentax CEO Fumio Urano in April 2007 and an announcement that the merger would not go ahead, the merger happened as originally planned.

The new company is focusing its main business on the following areas: life care, eye care, optics, information technology, imaging systems.

Pentax's main competitors include Canon, Leica, Nikon, Olympus and Sony.



  • PENTAX Industrial Instruments Co., Ltd.
  • PENTAX Optotech Co., Ltd.
  • PENTAX Service, Co., Ltd.
  • PENTAX Fukushima Co., Ltd.
  • PENTAX Tohoku Co., Ltd.
  • PENTAX Trading (Shanghai)Co.,Ltd.
  • PENTAX (Shanghai) Corporation
  • PENTAX Hong Kong Ltd.
  • PENTAX Cebu Philippines Corporation
  • PENTAX VN Co., Ltd.


  • PENTAX Europe GmbH
  • PENTAX U.K. Ltd.
  • PENTAX France S.A.
  • PENTAX Scandinavia AB
  • PENTAX Nederland B.V.
  • PENTAX Europe n.v.

North America

  • PENTAX of America Inc. (PENTAX Medical Company)
  • PENTAX of America Inc. (PENTAX Imaging Company)
  • PENTAX of America Inc.
  • PENTAX Medical Company
  • PENTAX Imaging Company
  • Microline PENTAX Inc.
  • PENTAX Canada Inc.
  • KayPENTAX (PENTAX Medical Company)

Agencies/Sole Distributors

See also



  • The Japanese Historical Camera. 日本の歴史的カメラ (Nihon no rekishiteki kamera). 2nd ed. Tokyo: JCII Camera Museum, 2004.
  • Cecchi, Danilo (1991) Asahi Pentax and Pentax SLR 35mm Cameras 1952-1989, Hove Photo Books, Sussex. ISBN-13: 978-0906447628

External links

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