Known and Unknown Pentax lens designers and their lenses

Known and Unknown Pentax lens designers and their lenses

I have tried to collect as much information as I can on who designed the Takumar and Pentax lenses. Currently I am only trying to identify as many Pentax lens designers as possible, and for each list what lenses each of them designed. When possible I add personal information and photographs of the designers. Eventually I hope to be able to specify one or several designers per lens, as well as finding out information on the designers career within AOCo, and who acted as mentor to which younger designer. This is work in progress. Please, if you find any misstakes, or if you know other information sources, please make a comment!

ORANGE = prototype never in serial production
GREEN = large uncertainty, only one source, conflicting sources, rumors etc.

It should be noted that I've found far more prototypes and patents that I've not included in the list, simply because I cannot figure out with enough certainty what the lens is intended to do. I should read more lens design...the optics I took as part of my education in Physics back in 1988 is not enough.
 
Important multisources representing previous attempts to collect similar information:

http://forum.xitek.com/thread-655516-1-1-2.html (in Japanese)
K-mount lens list (in Japanese)
http://pentaxstudy.bufsiz.jp (in Japanese)
http://www.ucatv.ne.jp (in Japanese)
http://blog.lovepenta.xyz (in Japanese)
http://www.marcocavina.com/articoli_fotografici/ (in Italian)
Foro pentaxeros.com (in Spanish)

Note that I have found several errors in the other lists of lenses and lens designers. Besides these links, online patent databases in japan, US, and EU, and my own printed library and notes on Pentax history have been used. Some things should be noted when you read the patents I link: i) Patents may not show exactly the same focal length or max apperture as the mass produced lense, but somewhere in the vicinity. ii) Patents often show more than one version of the lens design. That is normal. They often wish to secure their explicit rights to a new optical consept (or several) rather than a specific lens design, and must therefore show it applied in more than one way.

One feeling this work has given me is that it is not by accident these peeple have remained rather anonymous. Only the first of the lens designers, Mr. Suzuki, and during the 1990's Mr. Hirokawa, have become known by name in wider Pentaxian circles. This contrast to Olympus, Canon, Zeiss and Leitz where there have even been sort of a "hero worship" of the greatest optical designers. The designers behind the Pentax, Nikon, Konica and Minolta lenses remained mostly anonymous. I think this is more representative of much of the Japanese corporate culture. But I may be wrong. After Ricoh's purchase of Pentax in 2012 there appear to be some ambition to communicate better with the users, which have put the engineers in direct contact at least with fan-circles, see Pentax story: engineers interview. There do seam to be much more information available of Pentax loore, including lens designers, in Japanese on line sources, and to some degree in Europen on line sources, while English speaking web pages are more or less silent on the subject. So it has been vital to learn how to google in japanese...
It is unknown who designed the AOCo lenses pre-war, when the company produced 3rd party lenses for other companies, and during WWII.  It may have been Mr. Matsumoto himself, some employe, or perhaps Pentax mostly copied German designs. Therefore this story begins post WWII with the introduction of the m37 lenses for Asahiflex. The earliest patents are not available online digitally, but is well documented in other ways.

鈴木 亮平

Ryohei Suzuki

When the head of AOCo, Mr. Matsumoto, were to start manufactur single reflence reflex cameras (SLR) after the war, he purposedely recruited an experienced lens designer, Mr. Ryohei Suzuki, who had been working for Konishiroku (Konica). At this time, Konishiroku were still the gigant within the Japanese optical industry, even though it had been beaten badly during the war due to its large military optics production (as part of the Mitsubishi concern). Mr. Suzuiki in his turn introduced Mr. Matsumoto to Mr. Nobuyuki Yoshida, a former Konishiroku employee who now was running his own camera repair business, for the camera mechanics design. These three men became known as the Pentax-three. Mr. Suzuki designed all of the original lenses for the Asahiflex cameras in m37 mount, as well as several later Takumar lenses in m42 mounts. Some of his designs survived into the K mount era. Currently I'm trying to figure out if he were responsible for the simplification of the early (5:4) 135/3.5 lenses into a (4:4) version. In that case, his design survived into the 80's and the A135/2.8. It is likely that he were involved in the recruitment and training of the first generation of lens designers that followed after him as AOCo grow, such as Mr. Takahashi.

m37/ FF:
Asahi-Kogaku Takumar 50mm f3.5 (4:3) / produced 1953-
Asahi-Kogaku Takumar 58 mm f2.4 (5:3) / produced 1954-
Asahi-Kogaku Takumar 83mm f1.8 (7:4) / produced 1953-
Asahi-Kogaku Takumar 100mm f3.5 (3:3) / produced 1953-
Asahi-Kogaku Tele-photo Takumar 135mm f3.5 (5:4) / produced 1953-
Asahi-Kogaku Tele-photo Takumar 500mm f5 (2:1) / produced 1955-

m42/ FF:
Takumar 55mm f1.8 (6:5) / produced 1957- / http://www.klassik-cameras.de/Biotar_en.html
Takumar 58mm f2 (5:5) / produced 1957- / http://www.klassik-cameras.de/Biotar_en.html
Takumar 58mm f2.4 (5:3) / produced 1957- / same as the Asahi-Kogaku
Takumar 83mm f1.8 (7:4) / produced 1957- / same as the Asahi-Kogaku
Takumar 135mm f3.5 (5:4) / produced 1957- / same as the Asahi-Kogaku

Auto Takumar 55mm f1.8 (6:5) / produced 1960- / same as the Takumar version
Auto Takumar 85mm f1.8 (5:4) / produced 1960- /

Super Takumar 55mm f1.8 (6:5) / produced 1964- / same as the Takumar version
Super Takumar 85mm f1.9 (5:4) / produced 1964- / slightly modified version of the Auto 85/1.8
Super Takumar 135mm f3.5 (5:4) model I / produced 1964- / same as the Asahi-Kogaku

SMC Takumar 55mm f1.8 (6:5) / produced 1971- / same as the Takumar version
SMC Takumar 55mm f2 (6:5) / produced 1971- / same as the Takumar version
SMC Takumar 85mm f1.9 (5:4) / produced 1971- / same as the Super version

K / FF:
SMC Pentax 55mm f1.8 (6:5) / produced 1975- / same as the Takumar version
SMC Pentax 55mm f2 (6:5) / produced 1975- / same as the Takumar version
SMC Pentax-M 85mm f2 (5:4) / slightly modified version of the Takumar's 85/1.9 (5:4)

高橋泰夫

Yasuo Takahashi

Talented designer whom didn't only fill the gaps between Mr. Suzuki's lenses, but also made AOCo a leading expert on dedicated UV, IR and Ultra-Achromatic lenses. He created AOCo's first complete super-wide lens range from 24mm down to 17mm fish-eye. He is the father of the first pancake lens, copied by many other manufacturers, and which in modified form still is in production as the DA 40/2.8. His 50mm designs include both the famed 50/1.4 and 50/1.7 designs of AOCo. His most outstanding lens in my opinion is the 18mm f3.5. In all, he were the most influential optical designer at AOCo from mid 60's, to about 1980 (the spotmatic age and early K mount period). His legacy lasted well into the autofocus era, and you can still buy the FA50/1.4 and the new DA40/2.8 limited (pancake). Photo: screen capture from spy car in the James Bond 007 movie You only live twice, where one of Mr. Yasua Takahashi's quarts lenses appears (the lens to the right). I wonder how two Takumar lenses ended up in the movie? 
 

m42 / FF:
Super Takumar 17mm f4 (11:7) / produced 1967-1970 / patented 1970-06-02 (US) / patent US3515462 A / http://pentaxstudy.bufsiz.jp/Lensdesign/SMC-T17_40Fisheye/SMC-T17_40Fisheye_Design.htm / together with Mr. Kazamaki Tomokazu  
Super Takumar 24mm f3.5 (9:8) / produced 1967-1970 / patented 1967-07-24 (JP), 1968-07-10 (US) / Patent US3545845
Super Takumar 35mm f2 (8:7) model II / produced 1967-1970 / patented 1970-04-14 (US) / patent US3,506,336
Super Takumar 50mm f1.4 (7:6) model II / Gauss type / patented 1969-06-24 (US) / patent US3,451,745 / http://forum.xitek.com/thread-615464-1-1-2.html , https://codasky.wordpress.com/category/%E6%91%84%E5%BD%B1/page/5/ / together with Mr. Kazamaki Tomokazu  
Super Takumar 85-210mm f4.5 (11:10) / patented 1970-04-14 / patent US3506337  
Super Takumar 135mm f2.5 (5:4) / patented 1969-08-05 / patent US3459469A

SMC Takumar 17mm f4 (11:7) / produced 1971-1974 / same design as the Super Takumar  SMC Takunar 24mm f3.5 (9:8) / produced 1971-1974 / same design as the Super Takumar  SMC Takumar 35mm f2 (8:7) /produced 1971-1974 / same design as the Super Takumar model II  
SMC Takumar 50mm f1.4 (7:6) / produced 1971-1974 / same as the Super Takumar  
SMC Takumar 85-210mm f4.5 (11:10) / produced 1971-1974 / same design as the Super Takumar
SMC Takumar 135mm f2.5 (5:4) model I / produced 1971-1974 / same design as the Super Takumar  
SMC Takumar 135-600mm f6.3 (15:12) / produced 1971-1974 / patented 1970-03-17 / patent US3501224  
SMC Takumar 500mm (?) f8 (?) (4:4) reflex / patented 1970-01-20 (US) / patent US3490831A / prototype takumar reflex lens never manufactured!

Quartz-Takumar 85mm f3.5 / 1963  
Ultra-Achromatic-Takumar 85mm f4.5 / 1968 / http://www.dpreview.com/forums/post/40796757  
Ultra-Achromatic-Takumar 300mm f5.6 / 1968
 
K / FF:
SMC Pentax 17mm f4 (11:7) / same design as the Takumar's  
SMC Pentax 18mm f3.5 (12:11) / patent US3841736 / http://www.ucatv.ne.jp/~tweety/SuperWide/K18/K18_35_j.htm  
SMC Pentax 20mm f4 (12:10) / patent US3738738 / http://pentaxstudy.bufsiz.jp/Lensdesign/SMC-P20_40/SMC-P20_40_Design.htm  
SMC Pentax 24mm f3.5 (9:8) / same design as the Super Takumar
SMC Pentax 24mm f2.8 (9:8) / patented 1976-02-17 / patents US3938883, US-PAT4009944, JP-PAT S50-144435 / http://www.freepatentsonline.com/4217034.pdf, http://www.ucatv.ne.jp/~tweety/SuperWide/K24_28/K24_28_j.htm
SMC Pentax 35mm f2 (7:7) / same design as the Super Takumar model II  
SMC Pentax 50mm f1.4 (7:6) / same as the Super Takumar

SMC Pentax-M 35mm f1.4 / patented 1979-03-13 / patent US4143944 / http://pentaxstudy.bufsiz.jp/Lensdesign/SMC-PM35_14/SMC-PM35_14_Design.htm  
SMC Pentax-M 35mm f2.8 (6:6) / patent Sho 50-138824 / http://pentaxstudy.bufsiz.jp/Lensdesign/M35_28/M35_28_Design.htm, http://www.ucatv.ne.jp/~tweety/Wide/M35_28/M35_28_j.htm  
SMC Pentax-M 40mm f2.8 (5:4) / patented 1976-09-09 / patent Sho 53-33130 / http://www.marcocavina.com/articoli_fotografici/Pentax_M_40_2,8/00_p.htm, http://pentaxstudy.bufsiz.jp/Lensdesign/M40_28/M40_28_Design.htm, http://www.ucatv.ne.jp/~tweety/Standard/M40_28/M40_28_j.htm  
SMC Pentax-M 50mm f1.4 (7:6) / same as the Super Takumar  
SMC Pentax-M 50mm f1.7 (7:6) / Gaussian type / patented 1974-06-18 (US) / patent US3817603 / http://pentaxstudy.bufsiz.jp/Lensdesign/PM50_17/PM50_17_Design.htm  
SMC Pentax-M 75-150mm f4 (12:8) / patented 1982-05-25 (US) / patent US4331389A / together with Ogawa Ryota  
SMC Pentax-M 200mm f4 (6:5) / patent Sho 53-27422 / http://www.ucatv.ne.jp/~tweety/Telephoto/M200_40/M200_40_j.htm
 
SMC Pentax-A 24mm f2.8 (9:8) / same as the "K"-version  
SMC Pentax-A 35mm f2.8 (6:6) / same as the "K"-version  
SMC Pentax-A 50mm f1.4 (7:6) / nearly same as the Super Takumar, somehwat tweaked for sharpness  
SMC Pentax-A 50mm f1.7 (6:5) / same as the M version
SMC Pentax-F 50mm f1.4 (7:6) / same as the Super Takumar  
SMC Pentax-F 50mm f1.7 (6:5) / same as the M version
SMC Pentax-FA 50mm f1.4 (7:6) / same as the Super Takumar
SMC Pentax FA 50mm f1.7 (6:5) / same as the M version

Kazamaki Tomokazu

Mr. Kazamaki Tomokazu appears briefly on patents in the late 1960's and early 1970's when he worked mostly in pair with Mr. Yasuo Takahashi, but also developed on his own the new SMC Takumar 85mm f1.8 (6:6) lens solution that replaced the older (5:4) solution by Mr. Suzuki. Figure: His 85mm 6:6 design.
 
m42 / FF:
Super Takumar 17mm f4 (11:7) / patented 1970-06-02 (US) / patent US3515462 A / together with Mr. Yasuo Takahashi
Super Takumar 50mm f1.4 (7:6) / Gaussian type / patented 1969-06-24 (US) / patent US3,451,745 /http://forum.xitek.com/thread-615464-1-1-2.html , https://codasky.wordpress.com/category/%E6%91%84%E5%BD%B1/page/5/ / together with Mr. Yasuo Takahashi SMC Takumar 17mm f4 (11:7) / same design as the Super Takumar SMC Takumar 50mm f1.4 (7:6) / same design as the Super Takumar SMC Takumar 85mm f1.8 (6:6) / patended 1969-06-03 (US) / patent US3447858 A K / FF:
SMC Pentax 17mm f4 (11:7) / same design as the Takumar's
SMC Pentax 50mm f1.4 (7:6) / same design as the Super Takumar SMC Pentax-M 50mm f1.4 (7:6) / same design as the Super Takumar
SMC Pentax-A 50mm f1.4 (7:6) / same design as the Super Takumar
SMC Pentax-F 50mm f1.4 (7:6) / same design as the Super Takumar
SMC Pentax-FA 50mm f1.4 (7:6) / same design as the Super Takumar 6x7: Takumar 600mm f4 (6:5) / 1970-03-24 (US) / Patent US3502292 / together with Tohru Matsumoto
SMC Takumar 600mm f4 (6:5) /same as the Takumar

Tohru Matsumoto

Born in November 1935, Tokyo, Japan, the son of Mr. Saburo Matsumoto, director of AOCo. Mr. Tohru Matsumoto took a Master of Science in Management at M.I.T., Massachusetts, U.S.A. in 1963, and returned to work in his father’s company on the pentaprism problem, and lead the team that worked on a cost efficient serial-production system for pentagonal roof prisms (which was a major contribution to the large cost and price reduction per SLR body that enable AOCo to sell the Pentax Spotmatic for a fraction of their early pentaprism SLRs). To spend enough time on the optical research department to design his own lense was probably part of his training to take over the company after Matsumoto Sr. Not a bad apprentice exam.
In 1975 his father retired, and Tohru Matsumoto became the president of AOCo. In 1991-1996 Mr. Tohru Matsumoto was the director of Pentax UK limited, after which he retired. When no one in the next two generations was interested in taking over, this lead to the introduction of AOCo under the name Pentax on the stock market, which eventually allowed Hoya to make a hostile take over in 2007.
 
6x7: Takumar 600mm f4 (6:5) / 1970-03-24 (US) / Patent US3502292 / together with Kazamaki Tomokazu

SMC Takumar 600mm f4 (6:5) /same as the Takumar

Erhard Glatze

Born 1925, dead 2002. Famoused lens designer at Zeiss, Germany. His contribution to AOCo lens designs were part of a short period of colaboration between AOCo and Zeiss around 1974-1976, before Zeiss parted and begun working with Yashica. Either the AOCo leadership wasn't hapy with the design of the 15mm (world's first distortion-free ultra-wide angle lens), or they wanted to cut the costs, because they soon replaced it with another design without aspherical lens element. These are two of the Pentax lenses that unfortunately quite often is hacked (and destroyed) by Nikon users.
 
K / FF:
SMC Pentax 15mm f3.5 AL (13:12) model I / produced 1975 / soon replaced by version without aspherical lens by Mr. Sadao Okudaira

SMC Pentax 28mm f2 (9:8) / produced 1975- / same design as Zeiss Distagon 28mm f2 T*

Sadao Okudaira

The first lens designer at AOCo with Ph.D. degree in optics. Early in his career, the genious of Dr. Sadao Okudaira allowed him to redesign the "K" 15mm f3.5 by the legendary Mr. Glatzel at Zeiss without an aspherical element, but with nearly the same optical properties. Dr. Sadao Okudaira is also the lens designer that gave us the K and A 50mm f1.2 and the first "star" lens of Pentax, the M*300mm f4. He also worked on lenses for the growing market of 8-mm film and home VTR cameras, which AOCo manufactured under both the brand names Pentax and Cosmicar.



K / FF:
SMC Pentax 15mm f3.5 AL (13:12) model II / patented 1976-06-29 / patent US3966306 / Pentax replaced the Zeiss version with this version that achieved similar image quality without an aspherical element SMC Pentax 20mm f2.8 (12:10) / patented 1976-08-24 (US) / patent US3976367A / together with Yasuo Takahashi / prototype never serial produced
SMC Pentax 50mm f1.2 (7:6) / manufactured 1975- / patented 1987-10-27 / patent US4702568A /
SMC Pentax 50mm f1.2 (7:6) / patented 1983-02-16 /http://www.marcocavina.com/articoli_fotografici/Pentax_f_1,2_rifrazione_variabile/00_pag.htm / 3 prototypes with an element with internally variabel refractive index

SMC Pentax-M 35-135mm (12:9) / 1982-11-16 / patent US4359270 A / prototype never manufactured
SMC Pentax-M 35-70 f2.8-3.5 (7:7) / patented 1978-02-21 (US) / patent US4074931 /
SMC Pentax-M* 300mm f4 (8:7) / patented 1979-03 (JP), 1981-10-06 (US) / patent US4,293,197 / http://www.marcocavina.com/articoli_fotografici/Pentax_M_300mm_4_star/00_pag.htm / together with Koichi Kubayashi

SMC Pentax-A 24-50mm f4 (11:10) / patented 1983-09-27 / patent US4,406,523 / together with Sigetada Sato /
SMC Pentax-A 28-135mm f4 (17:15) / patented 1984-01-05 (DE), 1985-06-18 (US) /patents, DE3322640A1, US4523814 / patent contains several more lens solutions that were never manufactured SMC Pentax-A 50mm f1.2 (7:6) / same design as the K version
SMC Pentax-A 200mm (10:8 or 11:8) / patented 1985-08-03 (US) / patent US4556295 / prototype never in production
SMC Pentax-A* 300mm f4 (8:7) / same design as the M* version

SMC Pentax-F 24-50mm f4 (11:10) / same design as the A version

110 / APS-C:
Pentax-110 20-40mm f2.8 (8:8) / patented 1983-11-01 (US) / patent US4412725A / together with Satoru Tachihara 

 

Koichi Kubayashi

Koichi Kubayashi also had a Ph.D. degree in optics. He also worked on lenses for ultramicrofilm, and lenses in fluorit (unknown purpose).





K / FF:  
SMC Pentax-M* 300mm f4 (8:7) / patented 1981-10-06 / patent US4,293,197 / together with Mr. Sadao Okudaira

 
Sigetada Sato

Mr. Sigetado Sato's most impresive lens is the A*400 f2.8, a rare beast. He also designed the best of the A-generation normal zoomes, the A35-70 constant f4. Active at least from 1982 to 1989.
 
K / FF: 
SMC Pentax 24mm or 28mm (8:7 or 9:8) / patented 1987-04-28 (US) / patent US4660940A / prototype never produced / together with Ryota Ogawa

SMC Pentax-A 24-50mm f4 (11:10) / patented 1983-09-27 / patent US4,406,523 , DE3200949A1 / together with Sadao Okudaira /
SMC Pentax-A 35-70mm f4 rfe (7:7) / patented 1988-12-20, 1989-03-14 / patents US4812022, US4792215/
SMC Pentax-A* 400mm f2.8 ED IF (8:8) / 1985-10-08 / patent US4545654/ 

SMC Pentax-F 24-50mm f4 (11:10) / same design as the A version

 

Takahiro Sugiyama 

 

Ph.D. Dr. Takahiro Sugiyama was known as a wide angle expert. While AOCo didn't serial produce any of his original 20mm prototypes but went for the Zeiss design, he got revange in the M-generation when some of his wide angle designs were produced. It would be very interesting to see some photographs using his wide angle f1.4 prototype. Where they not produced because they were not so good, or because AOCo simple thought the market would be too small? Dr. Takahiro Sugiyama also worked on the TTL light measuring system of the Electrospotmatics, as well as the optics used for CD/DVD-discs. He was still working at AOCo around 1998. Employed at least from 1973 to 1998.
 
K / FF:
SMC Pentax 20mm f1.4 / patented 1975-04 (JP), 1978-06-20 (US) / patent US4095873 / http://www.marcocavina.com/articoli_fotografici/Pentax_20_1,4_M/00_pag.htm, Prototype shown at Photokina 1976, patent contains six alternative designs, never serial produced
SMC Pentax 20mm f2 or f2.8 (11:9 or 9 / patented 1979-04-25 (US) / patent US4150872 /  prototype never in production
SMC Pentax 24mm or 28mm f1.4 (9:7) / patented 1977-05-24 (US) / patent US4025168A / prototype never serial produced
SMC Pentax 28mm f2 / patented 1975-11 / Prototype 
SMC Pentax 30mm f2.8 to f3.5 (6:6) / patented 1976-05-11 (US) / patent US3955883A / prototype never serial produced

SMC Pentax-M 20mm f4 (8:8)
SMC Pentax-M 28mm f2 (8:7) / patented 1977-04-26 / patent US4019810 /http://www.freepatentsonline.com/3958864.pdf, http://pentaxstudy.bufsiz.jp/Lensdesign/D28_20/D28_20_Design.htm
SMC Pentax-M 40mm f2.8 (6:5) / 1980-09-23 (US) / patent US4223982A / prototype never serial produced

SMC Pentax-A 28mm f2 (8:7) / same design as the M version

 

Shigeo Kubota

Mr. Shiego Kubota also worked on UV optics and detectors and optical disc lenses. Were still at AOCo by 2000. Employed at least from 1976 to 2000.



K / FF:
SMC Pentax-M 28mm f2.8 model I / 1977 / patent JP 53-16627

小川良太

Ogawa Ryota 

Mr. Ogawa Ryota lead the development of the early Pentax autofocus system (ex. Patent number: 4890133, 1989-12-26). He also worked a lot on the optics for endoscopy, copiators, binocular and monocular (zooming) eyepieces, optical discs and scanners. His most famoused lens design is the A*85mm f1.4, which still live on slightly modified as the FA77mm limited, which share nearly the same lens design. Another favorit of mine is the M24-50mm constant f3.5, an unusual lens at its time, known as the "stack of primes" (24mm, 28mm and 35mm in one zoom lense with near prime quality). He were promoted to "Director of the Research and Development Center" of Pentax Corp. in June 1999. He were active approximately 1977-2007, after which he retired.

K / FF:
SMC Pentax 18mm f2 / 1974-08 / prototype http://www.marcocavina.com/articoli_fotografici/Pentax_18mm_f2_20mm_f2/00_pag.htm
SMC Pentax 20mm f2 / 1974-08 / prototype http://www.marcocavina.com/articoli_fotografici/Pentax_18mm_f2_20mm_f2/00_pag.htm



SMC Pentax-M 24-35mm f3.5 (9:9) / patented 1979-03-06 / patent US4142779 /
SMC Pentax-M 24-35mm f3.5 (9:9) / patented 1979-06-05 / patent US4157212 / alternative prototype never produced
SMC Pentax-M 75-150mm f4 (12:8) / patented 1982-05-25 (US) / patent US4331389A / together with Yasuo Takahashi
SMC Pentax 24mm or 28mm (8:7 or 9:8) / patented 1987-04-28 (US) / patent US4660940A / prototype never produced / together with Sigetada Sato



SMC Pentax-A* 85mm f1.4 / patented 1984-03-21 (JP), 1985-04-02 (US) / patent JPS5948723, US4508434 / http://www.google.je/patents/US4508434 / http://www.marcocavina.com/articoli_fotografici/Pentax_85_1,4_star, http://www.freepatentsonline.com/4157212.pdf, http://www.freepatentsonline.com/4142779.pdf

松尾 博文

Yasunori Arai

The work by Mr. Yasunori Arai includes two of the most fantastic lenses AOCo ever produced. The A*135mm f1.8 and the A*1200 f8. I own the first of these lenses, and it is a fantastic lens. I have no other lens that is so fast and yet perfectly sharp wide open. This may be the best lens Pentax have ever produced. I hope to discover more lens designs by Mr. Arai. He also worked on temperature correction of lenses, and on copying facsimile machine optics, and correction of chromatic aberration in astronomical lenses. Active from at least 1982 to 1987.

K / FF:

SMC Pentax-M 28mm f2.8 model II / patented 1984-08-28/ patents Sho 58-62610, US4468100 / together with Takayuki Ito / http://pentaxstudy.bufsiz.jp/Lensdesign/SMC-PM28_28II/SMC-PM28_28II_Design.htm

SMC Pentax-A 28mm f2.8 / same design as the M II
SMC Pentax-A* 135mm f1.8 / patented 1984-05-08 / Patent US4447137
SMC Pentax-Reflex-A ?mm f2.8 / patented 1989-06-20 (US) / patent US4840472A / prototype
SMC Pentax-A* 1200mm f8 ED IF (9:8) / patented 1984-12-12, 1987-01-23 / patents JPS59220711, JPS6214613 / together with Mr. Nobutaka Minefuji /

SMC Pentax-F 28mm f2.8 / same design as the M II and A

Satoru Tachihara

K / FF:

SMC Pentax-A 200 f4 (6:6) / patented 1985-11-05 / patent US4550987/ 

110:

Pentax-110 20-40mm f2.8 (8:8) / patented 1983-11-01 (US) / patent US4412725A / together with Mr. Sadao Okudaira

Masakazu Yamagata

Mr. Masakazu Yamagata specialised in macro lenses. He also worked on endoscope optics. Active from at least 1980 to 1988.

K / FF:

SMC Pentax-A 100mm f2.8 macro (9:8, 8:7 or 7:6) / patented 1987-03-31 (US) / patents US4653876A /three prototypes never produced

SMC Pentax-F 100mm f2.8 macro (9:8) / patented 1988-09-13 / patent US4770516 /

SMC Pentax-FA 100mm f2.8 macro (9:8) / same design as the F version

SMC Pentax-DFA 100mm f2.8 macro (9:8) / nearly same design as the F version

SMC Pentax-DFA 100mm f2.8 macro WR (9:8) / nearly same design as the F version

110:

Pentax 110 50mm f2.8 (5:5) / patented 1981-09-15 (US) / patent US4289385A

松尾 博文
Matsuo Hirofumi

Also worked with telescope design. Active from at least 1983 to 1990. Retired.

K / FF:
SMC Pentax-M 80-200 f4.5 model II (12:9) / patented 1988-04-26 (US) / patent US4740063A together with Mr. Takayuki Itoh

SMC Pentax-F 50mm f2.8 macro / patented 1990-05-08 / patent US4923292 /
SMC Pentax-F 70-210mm f4-5.6 ED rfe (13:9) / patented 1989-10-03 / patent US4871241 / 

SMC Pentax-FA 50mm f2.8 macro / same design as the F version

SMC Pentax-DFA 50mm f2.8 macro / patent Ping 1-214812

Nobutaka Minefuji

Ph.D.

K / FF:
SMC Pentax-A* 1200mm f8 ED IF (9:8) / patented 1984-12-12, 1987-01-23 / patents JPS59220711, JPS6214613 / together with Mr. Yasunori Arai /


6x7:
SMC Pentax 67 100mm f4 macro 1:1 / http://www.marcocavina.com/articoli_fotografici/Pentax_67_100mm_4_macro/00_pag.htm / together with Dr. Shuji Yoneyama patent includes several alternatives that were never built

Hiroyuki Hirano

I have so far only found two lenses designed by Mr. Hiroyuki Hirano, but the F/FA135mm is one of my favorit lenses. I hope he designed more lenses. Mr. Hiroyuki Hirano also worked on optics for copying machines and CCTV. At AOCo at least form 1986 to 1993.

K / FF:

SMC Pentax-F 60mm f2.8 or f4 SOFT (4:2) / patented 1990-08-14 (US) / patent US4948236A / prototype never produced
SMC Pentax-F 85mm f2.8 SOFT (5:4) / patented 1993-11-30 (US), 1994-02-17 (DE) / patents US5267086A, DE4033978C2
SMC Pentax-F 135mm f2.8 IF (8:7) / patented 1988-12-27 (US) / patent US4793698 /


SMC Pentax-FA 85mm f2.8 SOFT (8:7) / same design as the F version
SMC Pentax-FA 135mm f2.8 IF (8:7) / same design as the F version

Koichi Maruyama

Mr. Koichi Maruyama designed two of the most useful long star lenses in the F and FA generation: the F*300mm f4.5, and the F*250-600mm f5.6. Have also worked on UV optics and detectors. Were at AOCo at least from 1986 to 2000.

K / FF:

SMC Pentax-F* 300mm f4.5 ED IF (9:7) / patented 1988-07-30 (JP), 1994-04-06 (EU) / patents JP191161/88, EP0353649B1 / http://www.freepatentsonline.com/EP0353649A3.pdf
SMC Pentax-F* 250-600mm f5.6 EF IF (18:16) / patented 1989-07-18 / patent US4848883 / 

SMC Pentax-FA* 250-600mm f5.6 EF IF PZ (18:16) / same design as the F* version
SMC Pentax-FA* 300mm f4.5 ED IF (9:7) / same design as the F* version

泉水 隆之

Takayuki Sensui

Mr. Takayuki Sensui was born in 1964. He is responsible for several impressive lenses, including the two best normal zoomes in the FA generation: the FA*28-70 f2.8 as well as the FA28-70 f4 (where the later costed just a fraction, but performs just as well optically). His lenses also include the FA20-35mm, the FA35mm (which can still be bought new in the form of the slightly modified DA35/2.4), and the legendary FA*200mm macro. He left Pentax some time after 2002, and is now heading one of Nikon's lens design units. Active at AOCo/Pentax from about 1994 to 2002.

K / FF:

SMC Pentax-FA 20-35mm f4 AL GC (10:8) / patented 2001-06-12 / patents 2000-131611, 2000-131612, US6327098, US6246529B1 /
SMC Pentax-FA* 28-70mm f2.8 AL PZ rfe (14:11) / patented 1996-10-22 / patent US5568323 / 
SMC Pentax-FA 28-70mm f4 AL rfe (9:7) / patented 1998-07-28 / patent US5786942 / together with Mr. Kazunori Komori
SMC Pentax-FA 35mm f2 AL GC(6:5) / patented 2002-05-07 (US) / patents JP 2000-235145,US6,384,987B1 / http://pentaxstudy.bufsiz.jp/Lensdesign/FA35_20AL/FA35_20AL_Design.htm
SMC Pentax-FA 100-300mm f4.5-5.6 PZrfe bk (12:8) / patented 1994-09-13 / patent US5347399 / together with Mr. Shuji Yoneyama
SMC Pentax-FA* 200mm f4 macro ED IF (12:9) / patented 2002-03-19 / patents 2000-227546, US6359739 /

645:

SMC Pentax-FA 645 35mm f3.5 / patented 2001-07-21 / patent US20010007512 /

Shuji Yoneyama

Ph.D. Dr. Shuji Yoneyama's lens designs includes sseveral FA-generation zoomes, as well as the FA*200mm, and two of the latest 67 lenses. He was also involved in the design of binoculars with built in photographic function. 
Active at least from about 1994 to 2001.

K / FF:

SMC Pentax-FA 28-80 f3.5-4.7 PZ rfe bk (8:8) / patented 2000-06-20 (US) / patent US6078435A 
SMC Pentax-FA 28-80 f3.5-5.6 rfe sv bk (8:8) /same optical design as the PZ version
SMC Pentax-FA 24-90mm f3.5-4.5 AL IF GC (13:11) / patented 2000-10-03 / patent US6128140/ 
SMC Pentax FA 28-105mm f3.2-4.5 AL IF GC sv bk (12:11) / patented 2002-03-05 / patent US6353505 / 
SMC Pentax-FA 100mm f2.8 (6:6 or 7:7) / patented 2001-11-06 (US) / patent US6313955B1 / two prototypes with rear focusing
SMC Pentax-FA 100-300mm f4.5-5.6 PZrfe bk (12:8) / patented 1994-09-13 / patent US5347399 / together with Mr. Takayuki Sensui
SMC Pentax-FA* 200mm f2.8 ED IF (9:8) K / patented 1994-06-28 / patent US5325234 /

6x7:

SMC Pentax 67 90-180mm f5.6 / patented 2001-03-27 / patent US6208471 / together with Mr. Takashi Enomoto and Mr. Takayuki Ito
SMC Pentax 67 100mm f4 macro 1:1 / http://www.marcocavina.com/articoli_fotografici/Pentax_67_100mm_4_macro/00_pag.htm / together with Dr. Nobutaka Minefuji / patent includes several alternatives that was never built
 

 

Kazunori Komori

K / FF:

SMC Pentax-FA 28-70mm f4 AL rfe (9:7) / patented 1998-07-28 / patent US5786942 / together with Mr. Takayuki Sensui
 

Hiroyasu Ozaki

Mr. Hiroyasu Ozaki is responsible for several mediocre tele-zoomes.

K / FF:
SMC Pentax-FAJ 75-300mm f4.5-5.6 rfe (12:10) / patented 2002-11-19 / patent US6483649 /
SMC Pentax-FA 80-320mm f4.5-5.6 rfe sv bk (13:10) / patented 2000-04-18 / patent US6052235 /
SMC Pentax-FA 100-300mm f4.7-5.8 rfe sv (11:9) / patented 2001-07-05 / application US20010006433 /
 

村田 將之

Murata Masayuki

Active as lens designer at Pentax from about 1998 to 2003, when he moved to Sony.

K / FF:

SMC Pentax-FA* 31mm f1.8 / patented 2002-04-21 / patents 2002-040325, US20020034021/ together with Mr. Takayuki Ito /

645:

SMC Pentax-A645 120mm f4 macro / patent 2000-11-28 / patents US6154324/ together with Mr. Takayuki Ito

SMC Pentax-FA645 120mm f4 macro / same design as the A version

伊藤 孝之

Takayuki  Ito

Mr. Takayuki Ito begun his career with the design of the later M28/2.8 model, that later became the A28/2.8 and F28/2.8. He also designed medium format lenses, including the great 120mm macro lens design used for both the A645 120mm and FA645 120mm lenses. Mr. Takayuko Ito also designed TV and surveilance lenses (under the Cosmicar label). When Pentax required a faster lens than the prototype lens of Mr. Jun Hirokawa's (31mm f2.4 limited) he designed the final 31mm f1.8 limited together with Mr. Murata Masayuki around 2001. Among his lens designs are also two of the most useful APS-C zoom's, the DA10-17mm fisheye-zoom, and the DA*60-250mm. He also worked on UV optics, viewfinder optics, and CCTV optics (including a 180 degree fisheye). He were active at Pentax since the early 80's, and retired some time after 2008. Not to be mixed up with the actor of the same name.

K / FF:

SMC Pentax-M 28mm f2.8 model II / patented 1984-08-28/ patents Sho 58-62610, US4468100 / together with Mr. Yasunori Arai / http://pentaxstudy.bufsiz.jp/Lensdesign/SMC-PM28_28II/SMC-PM28_28II_Design.htm

SMC Pentax-M 80-200 f4.5 model II (12:9) / patented 1988-04-26 (US) / patent US4740063A /together with Mr. Hirofumi Matsuo

SMC Pentax-A 28mm f2.8 / same design as the M II

SMC Pentax-F 28mm f2.8 / same design as the M II and A

SMC Pentax-F 35-105mm f4-5.6 / patented 1990-04-17 / patent US4917482A

SMC Pentax-FA* 31mm f1.8 / patented 2002-04-21 / patents 2002-040325, US20020034021/ together with Mr. Murata Masayuki /

K / APSC:

SMC Pentax-DA 10-17mm Fish-Eye ED IF / patented 2008-01-08 / patent US7317581 / together with Mr. Jun Hirokawa / http://www.freepatentsonline.com/20070047096.pdf
SMC Pentax-DA* 60-250mm f4 ED IF SDM (15:13) / patented 2009-02-10 / patent US7489452 / http://www.freepatentsonline.com/20080043342.pdf / together with Mr. Chikara Yamamoto

645:
SMC Pentax-A645 120mm f4 macro / patented 2000-11-28 / patent US6154324/ together with Mr. Masayuki Murata /

SMC Pentax-FA645 120mm f4 macro / same design as the A version

6x7:

SMC Pentax 67 90-180mm f5.6 / patented 2001-03-27 / patent US6208471 / together with Mr. Takashi Enomoto and Mr. Shuji Yoneyama
 

Yasuyuki Sugano

 Designer of TV and surveilance lenses (Cosmicar).

平川純

Jun Hirokawa

Mr. Jun Hirokawa was born in 1962. He is probably the most influensal lens designer at Pentax since Mr. Yasuo Takahashi. His designes ranges from the two fish-eye zooms (FA17-28mm and DA10-17mm) to the F*/FA*600/4. Rumors have it that the FA limiteds were his own initiative, and he designed the FA43 ltd, redesigned the A*85/1.4 into the FA77 ltd, and made the first prototype of the FA31 ltd. Furthermore, his work includes several star lenses: as mentioned already the F*/FA*600mm, the FA*24mm, the FA*80-200/2.8, the FA*85mm and the DA*55mm. He worked for Pentax from the late 80's to about 2010. After the Hoya take-over of Pentax, he left Pentax, and is now working with lens design for Tamron. Rumors has it that the two full-frame f2.8 zooms that Pentax release in connection to the comming full frame body is bought from Tamron, and that they are in fact designes by Mr. Hirokawa. I haven't had time yet to dig up those patents.
Employed from from about 1986 to 2010.

K / FF:

SMC Pentax-A 35-80mm f4-5.6 rfe (7:6) / 1996-08-30 / Patent US5546232 / 

SMC Pentax-F 17-28mm Fisheye (9:7) / 1998-03-03 / Patent US5724193 / 
SMC Pentax-F 35-80mm f4-5.6 rfe (7:6) / same design as the A version
SMC Pentax-F* 600mm f4 ED IF (9:7) / 1990-02-27 / Patent US4904070 / 

SMC Pentax-FA* 24mm f2 AL / 1990-06-19 / Patent US4934797/ http://www.freepatentsonline.com/D338479.pdf

SMC Pentax-FA 28mm f2.8 AL / 1993-08-03 / Patent US5233474 /
SMC-Pentax-FA 28mm f2.8 softfocus / 1998-10-13 / Patent US5822132/
SMC Pentax-FA 28-105mm f4-5.6 AL PZ rfe bk (13:11) / 1993-11-23 / Patent US5264965 /

SMC Pentax-FA 31mm f2.4 limited / prototype, Pentax went for a faster version
SMC Pentax-FA 35-80mm f4-5.6 rfe (7:6) / same design as the A version 

SMC Pentax-FA 43mm f1.9 limited

SMC Pentax-FA 70-200mm f4-5.6 PZ rfe bk (10:8) / 1991-10-29 / Patent US5061053 / 
SMC Pentax-FA 77mm f1.8 limited / 2002-08-08 / modified version of the A*85mm design

SMC Pentax-FA* 80-200mm f2.8 ED IF (16:13) / 1996-11-05 / Patent US5572276/ http://www.freepatentsonline.com/5448412.pdf

SMC Pentax-FA* 85mm f1.4 (IF)
SMC Pentax-FA* 600mm f4 ED IF (9:7) / same design as the F* version

K / APS-C:

SMC Pentax-DA 10-17mm Fish-Eye ED IF / 2008-01-08 / Patent US7317581 / together with Takayuki Ito / http://www.freepatentsonline.com/20070047096.pdf
SMC Pentax-DA 14mm f2.8 / http://www.freepatentsonline.com/20050237627.pdf
http://www.freepatentsonline.com/7116499.pdf
SMC Pentax-DA 40mm f2.8 limited / modified from the M40/2.8
SMC Pentax-DA* 55mm f1.4 SDM / 2010-03-25 / Patent US20100073777 /

645:

SMC Pentax-A645 45mm f2.8 / 1988-05-31 / Patent US4747676 / 

SMC Pentax-FA645 45mm f2.8 / same as the A645 version
SMC-Pentax FA645 150-300mm f5.6ED IF / ??? 

加藤浩司

Kato Koji

Mr. Kato Koji designed two of the DA limited lenses, as well as the DA*300 mm. He also designed the most complex Q lens. He was part of the development team for Pentax K20D. Some time after 2012 he left Pentax for Sony. He were active as lens designer at Pentax from at least 2005 to 2012.

K / APS-C:

SMC Pentax-DA 21mm f3.2 limited / patented 2006-06-30 / patents 2007-225960,US7411746B2 / together with Mr. Masakazu Saori / http://www.freepatentsonline.com/20070201140.pdf, http://www.freepatentsonline.com/20070201141.pdf, http://www.freepatentsonline.com/7324293.pdf
SMC Pentax-DA 35 f2.8 macro limited / patented 2008-08-12 / patents 2008-298840, US7715118 / together with Mr. Yasuo Kanazashi / http://www.freepatentsonline.com/20080247058.pdf

SMC Pentax-DA* 300mm f4 ED IF SDM (8:6) / patented 2010-05-11 / patent US7715116 /
http://www.freepatentsonline.com/20080252996.pdf

SMC Pentax-DA50mm f1.8 / patented 2012-07 / patent 2012-167855

Q:

SMC Pentax-Q O4 Standard zoom 5-15mm f2.8-4.5 (8:7) / patented 2011-05-30 / Patent JP 2012-247689 (US2012307374, A1US20120307379 A1) together with Kunio Miura and Saori Masakazu

Chikara Yamamoto

Mr. Chikara Yamamoto also worked on Pentax spectacle glas. One reader commented that he may have moved to Fuji Film.

K / APS-C:

SMC Pentax-DA* 60-250mm f4 ED IF SDM (15:13) / patented 2009-02-10 / patent US7489452 / http://www.freepatentsonline.com/20080043342.pdf / together with Takayuki Ito 

金指 康雄

Yasuo Kanazashi

Mr. Yasuo Kanazashi designed two of the best DA limited lenses. Now at U. Kapton optics (own company).

K / APS-C:

SMC Pentax-DA 15mm f4 limited / patented 2009-03-27 (JP), 2010-02-11 (US) / patents 2009-116132 and 2010-044168, US20100033847 /

SMC Pentax-DA 35mm f2.8 macro limited / patented 2008-08-12 (US) / patents 2008-298840, US7715118 / together with Mr. Kato Koji / http://www.freepatentsonline.com/20080247058.pdf
SMC Pentax-DA 35mm f4 (8:6) / 2010-11-30 (US) / patent US7843651B2 / prototype never serial produced, might have been an alternative considered instead of the DA 35/2.4

雅和 小織

Masakazu Saori (Koori)

Mr. Masakazu Saori was born in Nishinomiya and graduated 2001 from Hokkaido technical university, and currently live in Kawagoe. He was employed by Pentax from about 2002 and until 2010 he had the opportunity to work with the optical master-mind Jun Hirokawa, before Hoya shot themselves in the foot and saced Mr. Hirokawa. Since 2010 the young apprentice has taken over Mr. Hirokawa's responsibilities and is leading the lens designer at Pentax/Ricoh.  He has designed most of the normal zoomes in the APS-C generation, as well as the DA*16-50mm, the DA*50-135mm, and two of the DA limiteds. He has also desinged at least two of the Q lenses. He is now leading the work with new full frame lenses.
In Pentax story: engineers interview 2017 Ricoh describes his responsibilities as "In charge of the interchangeable lenses ever since he joined the company... Now fully engaged in development and design of optical systems in general."

K/FF:

SMC Pentax-DFA* 70-200mm f2.8 ED (19:15) / patended 2010-10-02 / patent 2012-189817A / prototype, not the one in production
SMC Pentax-DFA* 70-200mm f2.8 ED DC AW (19:16) / Or so it is rumoured, but I have not seen the patent.

K/APS-C:

SMC Pentax-DA 12-24mm f3.5-f4.5 APS-C / patent JP 2012-63756 / proptype http://egami.blog.so-net.ne.jp/2012-04-03 but Pentax used Tokina design instead
SMC Pentax-DA 12-45mm f3.5-f4.5 APS-C/ patents US7508594, US7248416, US7230772 / http://egami.blog.so-net.ne.jp/2010-12-17-english / proptype
SMC Pentax-DA 16-45mm f4 / patented 2003-04 / patent 2004-354980
SMC Pentax-DA 17-70mm f4 / patented 2010-09-28 / patent US7804652B2 / http://www.freepatentsonline.com/20080297913.pdf
SMC Pentax-DA 18-55mm f3.5-5.6 WR / patented 2009-06-27 / patents US7253966 B2, US7307794 B2
SMC Pentax-DA 18-135mm f3.5-5.6 / patented 2010-11-26 / patent US7283311 B2 together with Maktoto Iikawa
SMC Pentax-DA 18-250 f3.5-6.3 ED AL IF / produced 2007-
SMC Pentax-DA* 16-50mm f2.8 / patented 2007-07-30 / patent US7301711 B2
SMC Pentax-DA* 50-135mm f2.8 / patented 2007-07-31 / patents US7289274 B1, 2007-212830/
http://www.freepatentsonline.com/20070188888.pdf, http://www.freepatentsonline.com/7289274.pdf
SMC Pentax-DA 70mm f2.4 limited / patented 2006-10-30, 2007-10-04 (US), 2009-06-02 (US) / patents 2007-264172, US7542219, US20070229983 / http://www.freepatentsonline.com/20070229983.pdf
SMC Pentax-DA 21mm f3.2 limited / patented 2006-06-30 / patent 2007-225960 / together with Mr. Koji Kato/ http://www.freepatentsonline.com/20070201140.pdf , http://www.freepatentsonline.com/20070201141.pdf, http://www.freepatentsonline.com/7324293.pdf, http://www.freepatentsonline.com/7411746.pdf

Q:

SMC Pentax-Q O2 Standard zoom 5-15mm f2.8-4.5 (8:7) / patented 2011-05-30 / Patent JP 2012-247689 (US2012307374, A1US20120307379 A1) together with Koji Kato and Kunio Miura 
SMC Pentax-Q O6 Telephoto zoom 15.45 - 43.64mm f2.8 / patents 2012-189817, US 20120229689

Makoto Iikawa

In Pentax story: engineers interview 2017 Ricoh describes his responsibilities as "In charge of lense tube mechanical design. Engaged in the design of the SMC Pentax-DA 18-135mm f3.5-5.6 AL (IF) WR, and also the Q-mount systems. Now fully engaged in the development and design of 645-mount / K-mount / Q-mount systems in general.".

K/APS-C:

SMC Pentax-DA 18-135mm f3.5-5.6 / patented 2010-11-26 / patent US7283311 B2 together with Masakazu Saori

大石 崇彦
Takahiko Oishi

Active at least from 2014 current date.
 
K/APS-C: 

SMC Pentax-DA* 11-19mm f2.8 (15:11 or 16.11, four examples) / patented 2016-01-12, 2016-12-09 / patent JP2016004093A , 2018-97053(P2018-97053A)

SMC Pentax-DA 20-40mm f2.8-4 limited DC WR / patented 2015-09-15 / patent Japanese 2015-11156 /

6X7:

SMC Pentax 67 70-180mm f5.6 / patented 2001-03-27 / patent US6208471 / together with Mr. Takayuki Ito and Mr. Shuji Yoneyama

小野崎龍之

Ono Kawasaki

Active at least from 2011 to current date.

K / FF:

SMC Pentax-DFA 60mm f2.8 macro/ patented 2012-03-12 / patent JP 2012-48084 / http://egami.blog.so-net.ne.jp / prototype downscaled from the DFA645 90mm macro

645:

HD Pentax-D FA645 MACRO 90mm F2.8 ED AW SR / patented 2013-01-29 (US) / patent US8363333 B2

Q:

SMC Pentax-Q O9 Telephoto 45mm f1.8 (10:7) / patented 2012-10-16 / patent
2014-081457 (JP) / http://blog.lovepenta.xyz/2014/05/pentax-09-telephoto-prime-lens.html / prototype

能村洋一

Nomura Yoishi 

Q:

SMC Pentax-Q O1 Standard prime 8.5mm f1.9 / patented 2012-10-25 / Patent 2012-226248 (JP), US20120268834 A1 together with Kunio Miura

三浦 邦夫

Kunio Miura

Q:

SMC Pentax-Q O1 Standard prime 8.5mm f1.9 / patented 2012-10-25 / Patent 2012-226248 (JP), US20120268834 A1 together with Nomura Yoishi
SMC Pentax-Q O2 Standard zoom 5-15mm f2.8-4.5 (8:7) / patented 2011-05-30 / Patent JP 2012-247689 (US2012307374, A1US20120307379 A1) together with Koji Kato and Saori Masakazu

榎本隆

Takashi Enomoto

Active at least from 2000 to current date.

6X7:

SMC Pentax 67 70-180mm f5.6 / patented 2001-03-27 / patent US6208471 / together with Mr. Takayuki Ito and Mr. Shuji Yoneyama
Q:SMC Pentax-Q O3 Fisheye 3.24mm f4.8 / patents JP 2013-40992, US20130038950 A1

Onozaki Ryuno, Masaru Eguchi, Hayakawa Koichiro

 

Mentioned as current lens designers still active at Pentax/Ricoh.

Some pending questions:

• Who designed the Takumar fish-eyes 17mm f11 and 18mm f11, and the A 16mm f2.8 fish-eye?
• Who designed the SMC Pentax-A/FA 20mm f2.8 lenses?
• Who designed the Super/SMC Takumar/Pentax 28mm f3.5?
• Who designed the sweet K 30mm f2.8?
• Who designed the Takumar 35mm f2.3, the first Japanese retrofocus wide angle?
• Who designed the Super Takumar 35/2 model I?
• Who designed the Auto/Super/SMC Takumar/SMC Pentax 35mm f3.5?
• The designer of the Takumar 35/4 is also unknown.
• Yasuo Takahashi made the Super Takumar 50mm f1.4 version 2 (7:6 elements), but who made the original (legendary) 8 elements version? 
• I haven't been able to find any information about the 105mm lenses, neither the Takumar/Auto Takumar 4 by 4 elements version, nor the Super Takumar/SMC Takumar/SMC Pentax 5 by 4 elements version. With this follows also the SMC Takumar/SMC Pentax 120mm f2.8, which is just an upscaled version of the 105mm f2.8 5 by 4 elements design.
• The M 120mm f2.8 is a different (5:5) design, also without known designer.
• Who simplified the early 135mm f3.5 (5:4) to the 4 by 4 design that was then used in all of the Super Takumar model II, the K 135/3.5, and in sligthly modified versions in the Takumar (bayonet) 135/2.5, Takumar Bayonet 135/2.8 and A 135/2.8. Or is it so that AOCo never patented this because it is straight of the original Ernostar design by Ludwig Jakob Bertele?
• Who made the SMC Takumar 135mm f2.5 model II (6:6) and its SMC Pentax (K) sibling?
• Who made the SMC Pentax-M 135mm f3.5 and 150mm f3.5, both the same 5 by 5 design?
• The SMC Takumar/SMC Pentax 150mm f4 (5:5) also lack known designer.
• Who desinged the A*200 mm macro? 
• Several 200mm lenses also lack designer: the Takumar/Tele-Takumar 200/3.5 and 200/5.6, as well as the SMC Takumar/SMC Pentax 200/4 (5:5) and the A 200/4 (6:6).
• Who designed the A* 300 f2.8 (8:8) and the FA* 300 f2.8 (10:7) lenses?
• The early 300mm f4 are also without known designers, from the Takumars (3:3 or 4:4) to the SMC Takumar (5:5) and the SMC Pentax (7:5).
• The same applies to the 400mm f5.6 lenses, neither the Takumar/K/M 5 by 5 elements version, the A 7 by 6 elements, or the FA 9 by 8 elements versions.
• Who designed the SMC Takumar/SMC Pentax 500mm f4.5 (4 by 4 elements)?
• Who made the A* 600 f5.6?
• Who made the SMC Takumar/SMC Pentax 1000mm f8 (5:5)?
• Who designed the Reflex lenses, the 1000mm f11, the 2000mm f13.5 and the 400-600mm f8-11? Yasuo Takahashi is a prime suspect due to his prototype mirror lens, but I have no evidence.
• Who designed the K 85-210mm f3.5?
• All early macro lenses, both in m42 and K mount, the 50/4 and 100/4 lenses, lack designer. Same applies to the related bellows 100mm lenses.
• I haven't come very far with the 67 and 645 lenses. First thing I should probably do is to compare with the patents I have found and related to 135mm film cameras, since I think I've heard that many of the medium format lenses are simply rescalled from these designs.

In any case, there is a lot of work left to do...