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Pentax is a Japanese lens and camera maker founded in 1919 under the name Asahi Optical Company. In 2002 it changed its name to Pentax Corporation. It is currently (2023) owned by Ricoh Imaging Corp.


The company that would become Pentax was founded in 1919 as Asahi Kogaku Kogyo G.K. (旭光学工業株式会社) . It was originally an optical company, beginning by making glasses under the Aoco brand (presumably the acronym of Asahi Optical Company), and made its first Aoco projection lens in 1923.[1] It began to produce camera lenses in the early 1930s under the leadership of CEO Kajiwara Kumao and his closest collaborator, Matsumoto Saburo.[2] These lenses were not marked as made by Asahi and were produced for various camera models made by other makers. From 1933 the company produced Optor and meniscus achromat lenses designed at Rokuoh-sha for Konishiroku models. From the mid-1930s to the end of World War II the company was also the main supplier of Molta, then Chiyoda Kogaku Seiko (predecessors of Minolta), whose cameras were equipped with Coronar and Promar lenses.[3][4]

The company changed status in 1938, becoming Asahi Kogaku Kogyo K.K. or Asahi Optical Co. based in Tokyo.[5]

After the war, Asahi made binoculars and polished lenses for several other companies. The first camera produced by Asahi, made as a prototype in 1951 and released in 1952, was the Asahiflex, which was also the first Japanese 35mm SLR. One of the models of the Asahiflex series, the Asahiflex IIb, was the first 35mm SLR to have an instant-return mirror, thus solving the problem of mirror blackout that had plagued SLRs up to that time (early SLRs left the mirror in its "up" position until the camera was wound for the next shot, blacking out the viewfinder).

A series of lenses bearing the name Takumar in honor of Kajiwara Takuma, brother of the founder, were developed for the Asahiflex, which used the 37mm screw mount (1952). The name Takumar was carried over to the 35mm M42x1 mount and 6x7 cameras and went through a series of iterations as build quality and coatings were developed with names such as Super-Takumar, Super-Multi-Coated Takumar, and SMC Takumar until 1975, when the name was changed to SMC-Pentax (even though Takumar lenses were in the catalog until 1979).

Pentax was originally the name of another 35mm SLR camera model, introduced in 1957 and successor of the Asahiflex. The name is derived from the shape of the prism used in SLR cameras (pentaprism), and the ending syllable deliberately looks like that of the Zeiss Ikon Contax. In fact, the name Pentax was a property of Zeiss Ikon (West) until they sold it to Asahi Optical Co., maybe strategically, because Zess Ikon's East-German concurrent had relabeled its Contax S SLRs to Pentacon.

Early Pentax cameras were sold in the USA stamped with the name Tower, the house brand of Sears Roebuck & Co., and many others carry the name Heiland, which was the importer and distributor in the USA. Heiland was later acquired by Honeywell until the partnership ended in 1976. These cameras were exactly the same as the ones stamped with the Asahi name.

Pentax was at the time one of the big Japanese camera manufacturers, given their success with 35mmSLR cameras such as the Asahiflex, the Pentax, and the Spotmatic lines. In 1969 Pentax introduced a complete camera systems for rollfilm, the Pentax 6x7. Later it introduced its tiny and popular Pentax Auto 110 for type 110 film cassettes.

In 1957 Asahi Optical Co adopted the M42x1 lens mount for the successful Asahi Pentax (AP) camera, which introduced the auto-diaphragm in the Auto-Takumar lenses for the K-camera and continued using it in the successful S/H line and in the Spotmatic. By 1975 Pentax tried to take the lead with a new lens bayonet, which overcame the limitations of the screw mount and maintained the same flange/film distance as that of the M42 screw mount, thus making it easier for lens makers to offer lenses for both mounts. In fact, the K mount should have been an open bayonet standard, and a handful of other renowned camera makers also used it, among them Pentax's K-mount: Zenit, Topcon, Chinon, Cosina,Ricoh, and Samsung. But most importantly, the mount was further developed and is still in use for Pentax's digital SLRs and even for one of its CSCs, making all new cameras back-compatible.

The company kept the name Asahi Optical Co. until it became Pentax Corporation in 2002. After successful prototyping since 2000 the company launched its first DSLR with a film twin in 2003, with Pentax K mount. A merger with the Hoya Corporation was completed on October 1, 2007. The new name became Hoya Pentax HD Corporation (HOYA-HD㈱).[6] In summer 2011 Hoya announced that it was selling the imaging branch of Pentax to Ricoh[7] while it will keep the medical branch of Pentax for itself.

In July 2011 Ricoh announced its intentions to purchase the Pentax photographic equipment business from Hoya (which, however, would retain some Pentax-branded medical product lines, etc.)[8]. In August of 2013 the name of the company was changed to Ricoh Imaging. It was announced that the Ricoh branding would be used on compact cameras, while Pentax-branded products would be the DSLRs, interchangeable-lens compact cameras, and binoculars.



Medium Format SLR

Interchangeable-lens compact

Interchangeable-lens mirrorless

Point and Shoot Cameras





  • Pentax EI-100
  • Pentax EI-3000 - prototype
  • Pentax Optio 330
  • Pentax Optio 430




  • Pentax Optio MX
  • Pentax Optio 30
  • Pentax Optio S40
  • Pentax Optio S4i
  • Pentax Optio 43WR
  • Pentax Optio S30
  • Pentax Optio S50
  • Pentax Optio S5i
  • Pentax Optio X
  • Pentax Optio 750z
  • Pentax Optio SV
  • Pentax Optio MX4


  • Pentax Optio WP
  • Pentax Optio 50
  • Pentax Optio S5n
  • Pentax Optio S45
  • Pentax Optio S55
  • Pentax Optio S5z
  • Pentax Optio SVi
  • Pentax Optio 60
  • Pentax Optio S60
  • Pentax Optio S6
  • Pentax Optio WPi
  • Pentax Optio 50L


  • Pentax Optio A10
  • Pentax Optio E10
  • Pentax Optio T10
  • Pentax Optio M10
  • Pentax Optio W10
  • Pentax Optio S7
  • Pentax Optio A20
  • Pentax Optio W20
  • Pentax Optio M20
  • Pentax Optio T20
  • Pentax Optio E20


  • Pentax Optio E30
  • Pentax Optio T30
  • Pentax Optio M30
  • Pentax Optio A30
  • Pentax Optio W30
  • Pentax Optio M40
  • Pentax Optio E40
  • Pentax Optio Z10
  • Pentax Optio S10
  • Pentax Optio A40
  • Pentax Optio V10


  • Pentax Optio E50
  • Pentax Optio M50
  • Pentax Optio S12
  • Pentax Optio V20
  • Pentax Optio W60
  • Pentax Optio M60
  • Pentax Optio E60
  • Pentax Optio E65


  • Pentax Optio P70
  • Pentax Optio E70
  • Pentax Optio E70L
  • Pentax X70
  • Pentax Optio E75
  • Pentax Optio W80
  • Pentax Optio P80
  • Pentax Optio E80
  • Pentax Optio WS80
  • Pentax Optio M85
  • Pentax Optio E85



  • Pentax Optio RZ18
  • Pentax Optio S1
  • Pentax Optio WG-1
  • Pentax Optio WG-1 GPS
  • Pentax RS1500

35mm film

Asahiflex SLR

Screw-mount Pentax SLR

The Spotmatic Series

These cameras were very successful, with a stop-down TTL light metering system that was simple, precise, and at affordable prices. Together with the Takumar lenses, it was one of the best selling cameras of the time. The family of cameras included:

With the advent of electronics, Asahi developed a camera that used that new technology; the Electro-Spotmatic had "electronic shutter" that was fully automatic and without steps.

Asahi also had budget models for entry level enthusiats:

K-mount manual focus SLR

Pentax K series

These cameras were launched in 1975, following the success of the Spotmatic, by replacing the M42 mount with K-mount while maintaining the same flange to film distance. Despite being the one with less features of this series, and due to its simplicity and robustness, the K1000 became the eternal student camera.

Pentax M series

Innovation in the form of miniaturization and cameras that were more compact, lighter, and reliable was introduced as the M line in 1976. This generation also brought the line of SMC-Pentax-M lenses. Aperture priority and the use of buttons instead of dials was a characteristic, together with very bright viewfinders with split image. Autofocus was introduced for the first time in a Pentax camera with the ME-F, which used a special lens with built-in focusing motor.

Pentax A series:

These cameras introduced electronic communication between the lens and the camera to allow for automatic exposure (Program mode). K-mount lenses with electronic contacts (SMC Pentax-A) were introduced to complement these cameras.

Pentax P series:

Pentax LX

  • Pentax LX (1980) Professional grade camera. LX refers to the 60th Anniversary of Asahi Optical Company.
    • Pentax LX 2000 - special edition for the year 2000

K-mount autofocus SLR

SF series

Z/PZ series

MZ/ZX series

A series of cameras that were popular in the late 1990s, the single-digit cameras were aimed at advanced amateurs, while the double digits were aimed to amateurs. All had plastic bodies and several program modes. The cameras used the MZ designation in the European and Asian markets and ZX in the Americas.


  • Pentax Espio IQZoom series (e.g. Espio, Espio 928, Espio 115, Mini, IQZoom 135M Date, Zoom60-X, Zoom95-WR)
  • Pentax PC series (e.g. PC-33, PC35 AF-M, PC-300 Date, PC-606W)
  • Pentax Mini Sport 35AF (35mm, f/3.8)
  • Pentax Pino series (e.g. Pino 35M)
  • Pentax Sport (DX)

645 Medium Format

Manual Focus


6×7 Medium Format


110 film

1979-1983 interchangeable lens SLR

APS film


Asahi Optical began as a lens fabricator. After World War II they also entered the camera business, and with the introduction of the Asahiflex they also introduced their own line of lenses, giving them the name Takumar. Takumar lenses were used in 35mm and the Pentax 6x7 until 1975, when the badge was replaced with smc-Pentax. Takumar lenses became legendary in the 1960s, with millions produced, and many are still used today on digital cameras.

Asahiflex (37mm) Mount

  • Standard lenses:
    • Takumar 50mm f/3.5 (three different versions)
    • Takumar 58mm f/2.4
  • Telephotos:
    • Takumar 83mm f/1.9 (both in Asahiflex and M42 with adapter mount)
    • Takumar 100mm f/3.5
    • Tele-Takumar 135mm f/3.5
    • Takumar 135mm f/3.5 (M42 with adapter)
    • Takumar 500mm f/5.0


The M42 lens mount uses a 42mm x1m screw and was introduced by VEB Zeiss after WW2.

It was adopted by Pentax for their SLR cameras in the 1950s, undert he name Takumar and developed until the 1970s

  • type 0 (1957): Takumar-preset: Replaced the older 37mm version of the Takumar line for the original AP cameras
  • type I (1959): Auto-Takumar: A lever is added to allow for full aperture focusing before shooting, for the Pentax K camera
  • type II (1962): Super-Takumar: Fully-automatic diaphragm that does not needs to be cocked manually, with an Auto/Manual switch on the lens. Single layer of coating; however, some later versions are multicoated as Asahi's coating technology improved. These lenses were made popular with the success of the Spotmatic cameras. The famous 50mm f/1.4 was introduced at that time.
  • type III (1971): Super-Multi-Coated Takumar: A seven-layer coating was applied for these lenses, the best available at the time, with improvements in contrast and color rendition. A mechanism for open-aperture metering with the Spotmatic-F/ES/ES-II was added to the lens.
  • type IV: SMC Takumar (1974): Identical optically to type III but uses a rubberized instead of the metal focusing ring and a different diaphragm ring as a prelude to the change of mount to K bayonet.
Wide Angles Normal Short - Teleobjectives Teleobjectives Zoom and Special lenses
  • 15/3.5 (III, IV)
  • 17/4 Fisheye (II, III, IV)
  • 18/11 Fisheye (II)
  • 20/4.5 (II, III)
  • 24/3.5 (II, III)
  • 28/3.5 (II, III)
  • 35/2.0 (II, III)
  • 35/2.3 (I)
  • 35/3.5 (I, II, III)
  • 35/4.0 (0)

  • 50/1.4 (II, III, IV)
  • 50/1.8 (I, II, III)
  • 50/3.5 (0)
  • 50/4 Macro (II, III, IV)
  • 55/1.8 (0, I, II, III, IV)
  • 55/2 (0, I, II, III)
  • 55/2.2 (0, I)
  • 58/2 (0)
  • 58/2.4 (0)
  • 83/1.9 (0)
  • 85/1.8 (I, III)
  • 85/1.9 (II, III)
  • 100/2 (0)
  • 100/3.5 (0)
  • 100/4 Bellows (0, III)
  • 100/4 Macro (III)
  • 105/2.8 (0, I, II, III)
  • 108/2.8 Index (III)
  • 120/2.8 (III)
  • 135/2.5 5 elements/5 groups (II, III)
  • 135/2.5 6 elements/6groups (III)
  • 135/3.5 (0, I, II, III)
  • 150/4 (II, III)
  • 200/3.5 (0)
  • 200/4 (II, III)
  • 200/5.6 Tele (II)
  • 300/4 (0, II, III)
  • 300/6.3 Tele (II)
  • 400/5.6 (II, III)
  • 500/4.5 (0, II, III)
  • 500/5 (0)
  • 1000/8 (0, III)
  • 70-150/4.5 (II)
  • 85-210/4.5 (II, III)
  • 45-125/4.0 (III)
  • 135-600/6.7 (III)

  • 85/3.5 Quartz Takumar (II)
  • 85/4.5 Ultra Achromatic (II)
  • 300/5.6 Ultra Achromatic (II)


K-mount was introduced in 1975, a bayonet mount for faster and more convenient operation than the M42 screw mount while preserving the Flange focal distance for back compatibility. The bayonet has a larger diameter, thus allowing for faster lenses and it simplifies the operation providing better alignment, and later the introduction of communication between camera and lens (A) and autofocus (AF). K-mount is still is use as of 2024, and compatibility is maintained even with the older lenses (Or M42 lenses with adapter).[10]

During this time Pentax have produced many different types of lens for the K-mount. They are summarized in the table below. [11]

Type Focus Focal Lengths Produced Zooms/Primes Lens Coverage Auto Aperture? Aperture Ring?
K Lenses Manual 15mm-2000mm Primes 36x24mm (35mm film) No Yes
M Lenses Manual 20mm-2000mm Both 36x24mm (35mm film) No Yes
A Lenses Manual 15mm-1200mm Both 36x24mm (35mm film) Yes Yes
F Lenses Screw-drive Autofocus 17mm-600mm Both 36x24mm (35mm film) Yes Yes
FA J Lenses Screw-drive Autofocus 18mm-300mm Zooms 36x24mm (35mm film) Yes No
FA Lenses Screw-drive Autofocus 20mm-600mm Both 36x24mm (35mm film) Yes Yes
D-FA Lenses Screw-drive Autofocus 50mm, 100mm (macros) Primes 36x24mm (35mm film) Yes Depends on lens
DA Lenses Screw-drive / SDM Autofocus 10mm-560mm Both APS-C Yes No
HD-DFA Lenses
for the K1 DSLR
Screw-drive / SDM Autofocus 10mm-560mm Both 26x24mm Yes No

6x7 Mount

645 Mount


Hand held

  • Pentax 1/21 Spotmeter
  • Pentax 3/21 Spotmeter
  • Pentax Spotmeter II
  • Pentax Spotmeter III
  • Pentax Spotmeter V
  • Pentax Digital Spotmeter
  • Pentax Digital Spot V

Asahi lenses on cameras from other makers

Not all examples of the cameras listed below have Asahi lenses.

Lenses not labeled as by Asahi

For Konishiroku:

For the predecessors of Minolta:

The Heliostar lenses were perhaps assembled by Asahi (see the discussion there).

Lenses labeled as by Asahi


  1. Yazawa, p.12 of Camera Collectors' News no.247.
  2. Yazawa, p.12 of Camera Collectors' News no.247.
  3. The Coronar and Promar lenses are attributed to Asahi in various sources, and this attribution is confirmed by the "Kokusan shashinki no genjōchōsa" ("Inquiry into Japanese cameras"), lens items Lb5, Lb39, Lc9, and N2.
  4. A brief history of the Asahi Optical Corporation by Derek J. White ARPS Spotmatic Magazine 32 -2002 - at the Asahi Optical Historical Club.
  5. Its address in 1943 was Tokyo-to Itabashi-ku Itabashi-cho. Source: "Kokusan shashinki no genjōchōsa" ("Inquiry into Japanese cameras").
  6. Japanese version of the news release (archived) found in the Hoya official website. The name "HOYA PENTAX HD Corporation" is written in capital letters.
  7. Summer 2011: Hoya confirms sale rumours. (archived)
  8. Hoya press release (archived) (PDF) on sale of Pentax assets to Ricoh
  9. Pentax Classic DSLR concept at Watch Impress
  10. Features of K mount at the Pentax K mount pages
  11. Evolution of the K-Mount at the Pentax K page


  • "Kokusan shashinki no genjōchōsa" (国産写真機ノ現状調査, Inquiry into Japanese cameras), listing Japanese camera production as of April 1943. Reproduced in Supuringu kamera de ikou: Zen 69 kishu no shōkai to tsukaikata (スプリングカメラでいこう: 全69機種の紹介と使い方, Let's try spring cameras: Presentation and use of 69 machines). Tokyo: Shashinkogyo Syuppan-sha, 2004. ISBN 4-87956-072-3. Pp.180–7.
  • Yazawa Seiichiro (?????). "Renzu no hanashi (157) Happi" (?????[157]????, Lens story [157] The Happy). In Camera Collectors' News no.247 (January 1998). Nishinomiya: Camera Collectors News-sha. Pp.11–4. (On the beginning of the company.)


Official websites

User groups and community websites

Technical information

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