The Pentax Papers, part 1, 1919 to 1973: From the founding of Asahi Optical Co. to the last screw-mount Pentax

The Pentax Papers, part 1, 1919 to 1973:

From the founding of Asahi Optical Co. to the last screw-mount Pentax

By Jason Schneider

In 1919 Kumao Kajiwara founded the Asahi Optical Joint Stock Co. in Otsuka, Tokyo as a “town workshop” turning out wearable eyeglasses and binoculars. By 1923 the company, by then known as Asahi Optical Co., introduced the first movie projection lens made in Japan. Now, more than a century later, the company that subsequently became the Pentax Corporation, was later merged into Hoya Corporation, and is now a wholly owned subsidiary of Ricoh Imaging, still makes superb Pentax branded eyeglasses and binoculars in addition to a full line of Pentax digital SLRs and lenses, and a popular range of digital all-weather action cameras.

In the lead-up to World War II, Asahi Optical, like virtually all other Japanese optical companies, devoted most of its energies to fulfilling Japanese military contracts for optical instruments. At the end of the war Asahi Optical was disbanded by the occupying powers, but it was allowed to re-form in 1948. It didn’t take this innovative company long to produce something truly exceptional, the very first 35mm SLR to be designed and manufactured in Japan!

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The Asahflex I of 1952 was the first 35mm SLR made in Japan. Featuring a fixed waist level viewfinder and manually set apertures, it was basic.

The Asahiflex I of 1952 was inspired by the prewar German Praktiflex but is no mere copy. A compact, beautifully made interchangeable-lens 35mm SLR with a non-removable waist level finder and an integral inverse Galilean optical finder for composing verticals, it has a horizontal travel cloth focal plane shutter with speeds of 1/20 to 1/500 sec plus B set via a rotating top-mounted dial, and a mirror that falls back into viewing position as the shutter release rises when finger pressure on the release is relaxed (it’s similar to the system previously used in the Italian Rectaflex in the late ‘40s, and is known as a “trigger-actuated” return mirror rather than a true spring-actuated instant-return mirror). All Asahiflexes including the Asahiflex I feature a 37mm diameter x 1mm pitch threaded mount that’s unique among analog SLRs, have hinged backs, and knob wind and rewind. The Asahiflex I measures 5.6 x 2.9 x 1.9 inches (W x H x D) and weighs in at 17.6 ounces. Standard lens was a manual diaphragm 50mm f/3.5 Asahi Kogaku Takumar (a Tessar type) and the first interchangeable lens was a 100mm f/3.5 Takumar. By 1953 Asahi introduced Takumar lenses with pre-set rings for quicker, more convenient aperture setting, but none of the Asahiflexes ever had an automatic aperture stop-down mechanism or offered semi-auto-diaphragm lenses. Because of their unique 37mm screw mount, original Asahiflex lenses are hard to find and often quite expensive.

To rectify some flash sync and shutter problems encountered with the Asahiflex I, Asahi brought forth the Asahiflex Ia (1953-1954) with the shutter speed numbers "normalized" to a series of B, 1/25, 1/50, 1/100, 1/200 and 1/500, and some experts assert that the shutter design was also “simplified for greater reliability.” A second flash terminal (X sync) was added above the first one. About 11,500 Asahiflex Ia cameras were turned out over its short production run.

The landmark Asahiflex IIB of 1954 to 1956 is generally credited with being the first 35mm SLR with an instant-return mirror mechanism, one that automatically returns the mirror to viewing position the moment the second shutter fires to terminate the exposure. Well, it turns out that the rare Gamma Duflex, an ingenious Hungarian 35mm SLR, already had this vaunted feature when it debuted back in 1947! However, the Gamma Duflex was and is notoriously unreliable because the small factory that made it didn’t have either the production engineering capacity to refine the design or the master craftsmen to assemble it. So, by default the Asahiflex IIB was the first widely distributed SLR with an instant-return mirror that worked! For the record, its other features closely parallel those of the Asahiflex Ia.

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The Asahiflex IIB was the first 35mm SLR with a reliable instant return mirror. Lens is the 58mm f/2.4 Takumar, then Asahi's fastest normal lens.

In many ways the nicest, most full-featured Asahiflex is the last of the series, the (out of numerical sequence) Asahiflex IIa of 1955 to 1957, prophetically introduced in the same year that Asahi Pentax Corporation was established in Japan as a sales company. The Asahiflex IIa carries forth the full feature set of the IIB including the instant-return mirror, and adds a front-mounted non-rotating slow speed dial with speeds of 1/25 to ½ sec. Some late production examples were fitted with 40mm screw mounts, and a handful were reportedly retrofitted with 42mm (M-42) mounts, but not at the factory. In 1957, the Asahiflex series was discontinued in favor of the bold new Asahi Pentax with an integrated eye-level pentaprism viewfinder, rethinking of the way Pentax made SLRs, and establishing the form and function of Japanese 35mm SLRs by many major makers for years to come.

The vicissitudes of Asahi Pentax and its corporate connections

And a tip if the lens cap to Wikipedia for providing most of the following facts:

The name "Pentax" was originally a registered trademark of the East German company VEB Zeiss Ikon (a contraction of “pentaprism” and “Contax”) acquired by the Asahi Optical company in 1957. Immediately afterward, the company, primarily known for its photographic products, distributed 35mm equipment under the name "Asahi Pentax" and medium format 120 6x7cm equipment under the sub brand "Pentax 6x7" (from 1969 to 1990) and "Pentax 67" (from 1990 to 1999). Equipment was exported to the United States beginning in the 1950s and up to the mid-1970s; being imported by Honeywell Corporation and branded "Heiland Pentax" and later "Honeywell Pentax". The company was officially renamed Pentax Corporation in 2002, and at the time was one of the world's largest optical companies, producing still cameras, binoculars, eyeglass lenses, and a variety of other optical instruments. In 2004, Pentax had about 6000 employees.

Merging with Hoya​

In December 2006, Pentax started the process of merging with Hoya Corporation (the well-known maker of photographic filters) 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 endoscopes, intraocular lenses, surgical loupes, biocompatible ceramics, etc. It was speculated that Pentax's camera business would be sold off after the merger. After a prolonged period of back-and-forth negotiations, the deal was consummated and on August 6, 2007. On October 29, 2007, Hoya and Pentax announced that Pentax would merge with and into Hoya on March 31, 2008.

Ricoh Imaging Company​

Japanese optical glass-maker Hoya Corporation stated on July 1, 2011, that it would sell its Pentax camera business to copier and printer maker Ricoh in a deal the Nikkei Business Daily reported was worth about 10 billion yen ($124.2 million). On July 29, 2011, Hoya transferred its Pentax imaging systems business to a newly established subsidiary called Pentax Imaging Corporation. On October 1, 2011, Ricoh acquired all shares of Pentax Imaging Corporation and renamed the new subsidiary Pentax Ricoh Imaging Company, Ltd. Under the agreement Hoya will continue to use the Pentax brand name for their medical related products such as endoscopes. On August 1, 2013, the corporate name was changed to Ricoh Imaging Company Ltd.


How did Asahi get the Pentax name? The bought it from Zeiss DDR!

To provide the most complete information on the remarkable VEB Zeiss Ikon prototype Pentax SLR of 1953-1954, we turned to (what else?) the zeissikonveb.de website, which tells the whole agonizing story of how the company strived to produce a world class camera in a communist controlled economy in excruciating detail. The following Google Translate English rendering of the original German text is a bit clunky in places, but the emotion comes through loud and clear.

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The original 1953 Pentax prototype by VEB Zeiss Ikon was an ingenious modular 35mm SLR. Unfortunately it never went into production.

“Do you think Pentax is a Japanese camera brand? The prototype of a camera, which was intensively worked on by the state-owned company VEB Zeiss Ikon in 1953/54 has been presented in the technical collection of the Ernemann main factory in Dresden. The name “Pentax” is clearly emblazoned on it, which is also a shortening of the phrase “Pentaprism Contax.” It is a cube-shaped 35mm SLR with a removable (film) magazine, an uncoupled light meter, and an attachable spring drive. With this new development VEB Zeiss Ikon wanted to regain its leading international position in camera construction.

However, the tradition of the associated protective documents discussed in detail below, shows that the development of this camera took place virtually parallel to the fateful events for the GDR in the spring and summer of 1953. After the state and party leadership had recovered from their state if shock, a radical reversal of economic policy ensured that completely new premises were set for the production of consumer goods. Series production of this complicated camera became hopeless because not only our foreign trade had been identified as having a low export potential, but also completely new standards had been set for satisfying domestic demand. VEB Zeiss Ikon was therefore left empty-handed. They quickly switched to producing a “people’s SLR camera” based on the West German model as the patent history shows. But despite having approximately 3,000 employees this large company had lost the so-called “leading function” in the fragmented Dresden camera factory. In addition, the threatened loss of (Zeiss Ikon) trademark rights to Zeiss Ikon AG in Stuttgart, these internal deficits were the second reason why VEB Zeiss Ikon had to cede its rights to the much smaller VEB Kamerawerke Niedersedlitz (formerly KW) in the course of 1951, and then in the following year was almost completely wiped out.

However, this Pentax project was only the second step. It had an immediate predecessor in the form of a roll film SLR camera which was also equipped with a removable cassette (film back) and worked with the nominal format of 4.5 x6cm. The intended name “Pentosix” appears in the literature, and the first indication that such a cube-shaped roll film reflex camera was being worked on is given by GDR patent number 5618 from September 11, 1952. It was registered by the heads of the research and development department at VEB Zeiss Ikon, Wilhelm Winzenburg and Heinz Schmidt. (Note: This camera never went into production.) As a reminder, that was at a time when the major problems with the Spiegel-Contax (the Contax 35mm SLR) had finally been overcome. Shortly after the series production had first started it turned out that their focal plane shutters did not work stably (were not reliable). At Zeiss Ikon it probably took the entire year of 1950 and a large part of 1951 to upgrade the focal plane shutter, to convert cameras that had already been delivered in large quantities, and to finally bring out a camera ready for series production with the Contax D model, which was introduced at the Spring Trade Fair in 1952. That was almost seven years after Wilhelm Winzenburg began the first design work on the Contax S in the summer of 1945, and by that time what had been a severe shortage of cameras right after the war had been replaced by fierce competition. There was therefore an urgent need to find a development that would allow the company to stand out from its competitors and imitators.”

Note: The legendary Dresden-based camera companies that were eventually subsumed under the state-owned VEB Pentacon umbrella never did produce a camera that took the international market by storm. Though their cameras generally had excellent lenses (a legacy of Carl Zeiss Jena) and were often fascinating mechanical designs, reliability was never their strong suit. Prakticas and Praktinas sold relatively well in Europe and the Pentacon Six had its charms, but overall, the East Germans, with the exception of Exakta, which was a separate entity, never achieved the international status or sales they were striving for, largely due to stultifying restrictions imposed by a communist regime that was still under the thumb of the Soviet Union.

The Asahi Pentax: The camera that made Pentax a household name

The Asahiflex IIa was a fine camera, but the company wisely realized it was a technological dead end. It lacked a pentaprism, making it difficult to shoot verticals and to follow many action subjects in its laterally reversed waist-level finder, despite its vestigial 50mm optical viewfinder. In 1954, Nobuyuki Yoshida, who had designed the Asahiflex body, made an initial prototype of a 35mm SLR with a pentaprism, and devised improved prototypes in 1955 and 1956. The last of these prototypes, still engraved “Asahiflex” on the front of the integral Pentax-style pentaprism housing, also has the distinctively contoured wind lever and folding rewind crank found on the first production Asahi Pentax, affectionately known as the “AP” among historians and collectors. Remarkably, when the Asahi Pentax (AP) was officially released in 1957 the pentaprisms were still made by hand, which inevitably increased the price of the camera. To keep future Pentax cameras affordable by ordinary consumers, Tohru Matsumoto invented a cost-effective method of producing high quality pentagonal roof prisms that was used in all Pentax SLRs starting with the Asahi Pentax S2/H2 of 1959.

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The original Asahi Pentax (AP) aka Pentax Original established the form factor for all 35mm Pentaxes to come. Lens is the semi-auto 55mm f/2 Auto-Takumar.

The Original Asahi Pentax of 1957: Setting the stage for the future

Note: I am indebted to Dario Bonazza and his authoritative 1997 article commemorating the 40th Anniversary of the original Asahi Pentax posted by the Asahi Optical Historical Club, as the source of most of the following information:

In May 1957, Asahi Optical Co, introduced the Asahi Pentax, its stylish new fixed-pentaprism SLR. This was the beginning of the acclaimed Asahi Pentax line which would be improved step-by-step over the next twenty years. Its elegantly contoured, compact (but taller than the Asahiflex), octagonal body has rounded corners, a well-designed control layout, and an exquisitely proportioned pentaprism housing (bearing the now classic arc over the Asahi Pentax name), all of which gave the Asahi Pentax its distinctive style. The camera’s stylish design, high quality finish, and masterful construction contributed greatly to the success of Pentax cameras, making the Pentax seem more refined than many of its competitors. To complement its high-quality exterior finish and styling, the Asahi Pentax was a reliable and well-engineered camera on the inside as well. Indeed, the reliability of Asahi Pentax cameras placed them among world's finest.

Internal and external innovations

The Asahi Pentax was one of the most innovative cameras of the era, and it introduced technical improvements and specifications that would set industry standards. The Asahi Pentax was the first Japanese SLR with fixed pentaprism viewfinder for direct eye-level viewing and it has been acknowledged as the world's first SLR with a right-hand wind lever (the Exakta had a left-hand one, while all other SLR's of the pre-Nikon F era had knob wind). It was also the first with a folding rewind crank, and the first camera with both an eye-level prism and instant return mirror (the Asahiflex IIB had instant return mirror only). Some experts note that the Asahi Pentax was the first SLR with a microprism on the focusing screen. Perhaps most important is its iconic form factor, which was so well thought out that the shape and look remained unchanged up to the Pentax SP1000 model of 1974. One small but significant improvement is the top shutter speed dial, which indicates the correct shutter speed whether the shutter is cocked or not. On the Asahiflex, the selected shutter speed is only visible when the shutter is advanced (cocked). Other small upgrades: the shutter release now has as standard cable release thread, and the neck strap lugs are more robust and are positioned higher, and more conveniently, at the top of the body. Finally, the Asahi Pentax has a restyled slow speed dial with a 1 sec speed that the Asahiflex IIa lacked.

Variations, Registered Numbers and Standard Lenses

The Asahi Pentax Original was the first Asahi camera available in either satin chrome or all black finish, the latter being rare. The black version was equipped with a matching all black standard lens, while the chrome one had chrome finished aperture and depth-of-field rings. The Asahi Pentax was also sold by Sears, Roebuck and Co. as the Tower 26. The Asahi Pentax model of 1957 had a six-digit serial number. Six-digit numbers were continued on later model Asahi Pentax cameras up to 1964. Registered serial numbers range from 132691 to 153211 (approximately 132500 to 154000 according to Pentax historian Fred Sherfy). However it is believed that fewer than 20,000 units were produced. The standard lenses for the Asahi Pentax were the 58mm f/2 Takumar, the 55mm f/2.2 Takumar, and the 58mm f/2.4 Takumar in Pentacon/Pentax M42x1 screw mount. The Tower 26 version of the camera was only sold with the 58mm f/2.4 lens.

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Rare black version of the Asahi Pentax S with 55mm f/2.2 Takumar lens. Only about 400 were made, making it a rare and pricey collectible.

A variation of the Asahi Pentax Original was the Asahi Pentax S that was introduced in April 1958 and discontinued in May 1959. Visible differences between the Asahi Pentax and the Asahi Pentax S include the different progression of shutter speeds (with the latter featuring the modern geometric progression of speeds) and a different film reminder dial. The film reminder dial on the S is the same as that found on the next Asahi Pentax K (the third and last model of the first series of Asahi Pentax cameras). Since the Asahi Pentax S was sold at the same time as the Pentax K, it can be considered a budget version of the Pentax K. The Asahi Pentax S was also available in either satin chrome or all black finish, both being uncommon. The Asahi Pentax S also had the S model designation 'S' marked below the serial number. A few early bodies have been reported in the literature with no model designation at all. It is possible these examples represent damaged Asahi Pentax S cameras with top housing plates replaced with spare AP plates, bearing the AP lower serial numbers. Registered serial numbers for the Asahi Pentax S range from 150981 to 165354 (154000 to 162000 according to Fred Sherfy) and a total production of less than 4,000 units has been cited in Sherfy’s book. It has been reported that fewer than 10% of Asahi Pentax S models were finished in black, making them rare birds that fetch fancy prices. The standard lenses for the Asahi Pentax S were the 55mm f/2.2 Takumar or the 55mm f/1.8 Takumar, all in Praktica/Pentax M42x1 screw mount.

Specifications of the Asahi Pentax Original (AP) and Asahi Pentax S

Construction: aluminum die-cast chassis with brass housings

Lens mount: Pentax M42 screw mount (42mm diameter x 1mm pitch)

Flange focal distance: 45.5mm

Exposure: manual

Exposure meter: not available

Shutter: mechanical, horizontal travel, rubberized silk focal plane

Shutter cocking: ratchetted lever with 180° standoff angle

Shutter speeds:

Asahi Pentax: B,T,X ,1, ½, 1/5, 1/10, 1/25, 1/50. 1/100, 1/200. 1/500 sec.

Pentax S: B,T,X, 1, ½, 1/4, 1/8, 1/15/1/30, 1/60, 1/125, 1/250, 1/500 sec.

Flash synchronization: around 1/45 sec.

Shutter release: mechanical with standard thread

Self-timer: none

Viewfinder: fixed pentaprism

Focusing screen: fixed ground glass with microprism grid

Viewing area: unknown

Magnification: 1X with 55mm lens at infinity

Viewfinder readouts: none

Power source: none

Dimensions: 145 x 92 x 50mm (W x H x D, body only

Weight: 570g without lens

Other features: automatic frame counter with manual reset, X and FP standard sync sockets, non-interchangeable hinged back, rewind button and tripod socket on bottom plate, loaded film reminder dial.

Production period: Asahi Pentax (AP), May 1957 to April 1958; Asahi Pentax S, April 1958 to May 1959.

The Asahi Pentax K: A lot more than a tweaked Asahi Pentax S

The Asahi Pentax K, introduced in May 1958, was the final development of the first-generation pentaprism SLRs from Asahi Optical Co. Ltd. The Asahi Pentax K was introduced in May 1958, just one month after the release of the Asahi Pentax S. At first glance, it appears to be a minor variation of its predecessor, the Asahi Pentax S, but things were quite different both inside and outside.

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The Asahi Pentax K with 55mm f/1.8 Auto-Takumar lens. Note chrome or finished semi-auto-diaphragm cocking lever on right side of lens.

The first clue that the Asahi Pentax K offers more advanced features is its new standard lens, the Auto-Takumar 55mm f/1.8, that sports a chrome finished diaphragm cocking lever. Remove the lens and you can see both a protruding pin on the lower part of the back of the lens that mates with moving plate inside the base of the M42 mount. That is a diaphragm actuation plate, first introduced in the East German Praktica FX2 of 1955. This diaphragm actuation plate is coupled to the shutter release, so when the lens is opened to full aperture by pressing the spring-loaded diaphragm cocking lever to the “open’ position, and the shutter release is pressed to take the picture, the moving plate behind the lens mount springs forward, contacts the pin at the back of the lens and stops the lens down to the set (working) aperture just before the shutter fires. This is known as semi-automatic diaphragm, “semi” because you must manually cock the lens prior to each exposure. The diaphragm release plate stays forward as long as the release button is depressed, but this is not a drawback since the 'Auto' lens only reopens to maximum aperture when you cock the lever again. Another improvement over previous Asahi Pentax models was the addition of a 1/1000th top shutter speed. Some say the "K" designation, refers to “kilo” a prefix meaning 1000, an oblique reference to the top shutter speed; others assert that “K” refers to “king,” the top model in the series. Framing and focusing were facilitated by a brighter Fresnel screen and for the record the rewind crank was changed from chrome to black.

Overall Asahi Pentax K was a thoughtful refinement of the original Asahi Pentax models. However, the model S was not discontinued immediately after the introduction of the K and the two cameras remained in production side by side until May, 1959. Today, the Asahi Pentax K is far more common than the S on the camera collector market, indicating that it was a greater commercial success. FYI, it happens to be my favorite vintage Pentax— I own two, and the 55mm f/1.8 Auto-Takumar is great!

Variations, Registered Numbers and Lenses

The Asahi Pentax K was available in either satin chrome or all black finish, the latter being far less common. The black version of the K was equipped with a matching black standard lens, with the diaphragm cocking lever as the only chrome feature, while the chrome version also had chrome finished aperture and depth-of-field rings and black and chrome focusing ring, which was in fashion in German cameras of the era. The model K was the last Asahi Pentax camera sold by Sears, Roebuck and Co., marketed under their brand name as the Tower 29.

The Asahi Pentax K had the model designation marked below the 6-digit serial number on the top plate, to the left of the pentaprism, the position of serial numbers in all screw mount Pentaxes. Serial numbers registered by the author range from about 154000 to 182000, but some S models also fall within this range. It’s estimated that between 20,000 and 25,000 Asahi Pentax Ks were produced.

The only standard lens for the Asahi Pentax K was the 58mm f/1.8 Auto-Takumar. Soon after the 55mm f/1.8 appeared, the new wide-angle Auto-Takumar 35mm f/2.3 and the medium-telephoto Auto-Takumar 105mm f/2.8 appeared, both featuring semi-automatic diaphragm operation. The Asahi line of Takumar lenses for the K also included the 35mm f/4, one of the early wide-angle retrofocus designs, the much-admired 83mm f/1.9, the 100mm f/3.5, the 135mm f/3.5, the 300mm f/4, the 500mm f/5 and the 1000mm f/8, all featuring manual diaphragms. In 1958, the Asahi Pentax system included a total of 10 interchangeable lenses ranging from 35mm to 1000mm and was already a well-established system. By today’s standards it was a little short on the wide-angle end, but many other SLR systems of the era still offered no retrofocus wide-angles and most camera manufacturers still had no SLR lens system at all. It’s worth noting that Pentax, unlike other manufacturers, never sold wide-angle lenses of symmetrical design, which required the mirror to be locked up before mounting, thereby losing reflex viewing ability. Asahi designed retrofocus wide-angle lenses from the beginning, thus allowing full SLR viewing and focusing to always be available.

Asahi Pentax K Specifications:

Construction: aluminum diecast body with brass housings

Lens mount: Pentax M42, 42mm diameter screw thread x 1mm pitch

Flange focal distance: 45.5mm

Exposure: manual

Exposure meter: not available

Shutter: horizontal travel rubberized silk focal plane

Shutter cocking: ratcheted lever with 160° standoff

Shutter speeds: B, T, X, 1, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, and 1/1000 sec.

Flash sync: approximately 1/45 sec.

Shutter release: mechanical with standard thread for cable release

Self-timer: none

Viewfinder: fixed eye-level pentaprism

Focusing screen: fixed ground glass with microprism grid

Viewing area: unknown

Magnification: 1X with 55mm lens at infinity

Viewfinder readouts: none

Power source: none

Dimensions: 145 x 92 x 50mm (W x H x D) body only

Weight: 580g, body only

Other features: Automatic frame counter with manual reset, X and FP standard sync sockets, non-interchangeable back, rewind button and tripod socket on bottom plate, loaded film reminder dial.
Period of production: May 1958-May 1959.

Tne Asahi Pentax S2 of 1959, marketed in the U.S. as the (Honeywell) Heiland Pentax H2, was produced in two versions, the latter with a notch on the shutter speed dial that couples with a new top-mounted CdS light meter that was introduced in 1960. Also, unlike the K, all shutter speeds (1/500 sec to B) are on single non-rotating top-mounted dial. There was also a less common black version, another labeled “SB” sold only at Japanese military bases, and a few rare examples engraved “Asahiflex.”

The Asahi Pentax S3 debuted at Photokina 1960 along with a prototype of the revolutionary Pentax “Spot-Matic,” which created a sensation. Production of the S3, which features a 1/1000 sec top shutter speed, began in 1961, but some early examples had shutter speed dials that top out at 1/500 sec. Some S3s were fitted with a 55mm f/1.8 lens labeled “Auto-Takumar,”but it was really the first Super-Takumar with a fully automatic diaphragm! The Asahi Pentax S3 measures 144 x 92 x 50mm (W x H x D) and weighs in at 580 g, both stats body only. Military variants oddly labeled “SB2” were also produced. The Asahi Pentax S1 was a budget-priced model identical to the late S2 and, has a top shutter speed of 1/500 sec, and was typically fitted with a 50mm f/2.2 Auto-Takumar lens with semi-auto diaphragm.

The Asahi Pentax SV of 1962 was the last top-tier model in the S series and features a new self-timer located unconventionally under the rewind crank! To set it you turn a knurled ring clockwise to the V mark, and the camera will fire 10 sec later when you press the shutter release. Most SVs are fitted with a 55mm f/1.8 Auto-Takumar lens, but later versions were configured to accept the forthcoming f/1.4 Takumar. The SV measures 144 x 92 x 50mm (W x H x D) and weighs in at 590g, both specs body only. The economy Asahi Pentax S1a of 1962 lacks the self-timer, the f/1.8 lens and the 1/1000 sec top shutter speed (though the shutter speed dial has a detent past the 1/500 sec mark that provides an “uncalibrated” 1/1000 sec speed!) Evidently it was cheaper to use existing parts to create a downscale model, a strategy later used in creating the Pentax Spotmatic SL and SP 500.

Pre-Spotmatic Pentax Production

Excerpted from “Asahi Pentax from 1957 till 1964” www.pentax-slr.com

Model Year of production Numbers produced



Asahi Pentax 1957-1958 19,546

Asahi Pentax S 1958-1959 4,900

Asahi Pentax K 1958-1959 21,454



Asahi Pentax S2 (H2/SB) 1959-1963 130,892

Asahi Pentax S3 (H3/SB2) 1961-1963 361,215

Asahi Pentax S1 (H1) 1961-1963 46,500

Asahi Pentax SV (H3v) 1963-1968 481,696

Asahi Pentax S1a (H1a) 1963-1968 135,352



In addition, S2 Super, for the Japanese market: 52,500



Total production S-series: 1957-1968: 1,254.055



Production numbers for 1957-1959 includes Sears Tower models sold in the USA

The H-series was sold almost only in the USA. (Some H2s were sold elsewhere.)

The SB and SB2 were sold only in Japanese military bases.

Numbers also include Asahiflex/Pentar/Penta H2 and Pentar branded S and K cameras.

The Pentax Spotmatic: One of the most successful SLRs of all time!

The Asahi Pentax Spotmatic was one of the greatest successes in the history of camera manufacturing. Launched as a fully functional prototype at the Photokina exposition of 1960, it was produced from 1964 (original model) to 1976 (the open-aperture-metering Spotmatic F), and total production of the Spotmatic family came to an astonishing 4 million units!

The Spot-Matic prototype Asahi Optical Co. showed at Photokina 1960 was revolutionary, with a light measuring system located in a small arm in the center of the viewing area, effectively metering light as a spot-meter. This design was used several years later, as technology advanced, in cameras such as the Leica CL and the Leica M. However, at the time technological limitations made it impractical and Asahi’s engineers looked for other solutions.

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The Asahi Pentax Spotmatic, shown here with 55mm f/1.8 Super-Takumar lens with auto diaphragm, was wildly successful and widely imitated.

The Spotmatic (no longer hyphenated) camera was launched to the public in 1964, and by that time the metering system had been changed to what was essentially a center-weighted-averaging metering system using 2 small CdS cells, one on each side of the viewfinder, that read off the focusing screen and cover the whole picture area. A switch on the side of the mirror housing activates the light meter, which reads at working aperture (stopped down) and a match needle in the finder is used to set the exposure. This light metering system was so straightforward and successful that it was adopted by numerous other camera companies and set the standard for the industry. The change in the metering system was not reflected in the marketing materials, and the original name continued to be used. Some wags have suggested that Asahi was really aiming for a spot meter, settled for an averaging meter, but called it a Spotmatic anyway, but this is highly unlikely. The engineers probably realized that, in a camera with a single metering pattern, an averaging system would yield more consistent exposures in the hands of the average consumer, which was Asahi’s aim point.

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Honeywell Pentax badged Spotmatic in beautiful black. Its 50mm f/1.4 Super-Takumar lens is superb, and the later SMC version was even better.

Focusing the Spotmatic relatively easy, the finder is bright corner to corner due to its Fresnel lens and a "microgrid" at the center of the image fractures the image when not in focus. Significantly, the Spotmatic represented a radical departure from previous Asahi SLRS,
a completely new design inside and out. Its chassis and mirror box are made of aluminum, the mirror mechanism was improved, and more important, the shutter was a new design with a projected life of 100,000 cycles, up from 20,000. Flash sync was now at 1/60 sec instead of 1/50, and the new focusing screen design resulted in a brighter viewfinder that was easier to focus. The film guide rails were made wider, and the pressure plate elongated to keep the film flatter, and the self-timer mechanism was upgraded. Over the course of the production of the Spotmatic, over 100 internal changes were made to the camera, including improved focusing screens (the microgrid in the later versions is finer and more precise), more reliable mirror mechanism, changes to the light meter switch, etc.

Although Topcon RE Super of 1963 edged out the Pentax Spotmatic as the first TTL-metering SLR on the market, its design, which placed the CdS cells behind slits in the reflex mirror, was more compiicated and expensive to manufacture and not adopted by other manufacturers. No other SLR of its era came close to the marketing success of the Spotmatic, and some experts assert that it sold in larger quantities than Nikon and Canon combined.

Asahi Pentax Spotmatic (aka Spotmatic SP) specifications

Type: SLR body

Manufacturer: Asahi Optical Co.

Year of launch: 1964

Film: 35mm cartridges, early models had speed range ASA 10-800; after 1965, ASA 20-1600

Viewfinder: fixed eye-level pentaprism viewfinder 0.88x magnification with 50mm and life-size with 55mm lens at infinity.

Lens Mount: Pentax/Praktica screw thtead mount (M42x1mm)

Shutter: Horizontal travel cloth focal plane shutter speeds 1 - 1/1000 sec., flash sync at 1/60 second

Metering: CdS TTL averaging metering (stopped down manual match-needle metering system) EV 3~18 (ISO 100) early models and 1.7 ~ 18 (ISO 100) later models.

Power: 1.35v OX400 mercury cell

Flash: FP or X

Dimensions: 143 x 92 x 50 mm (5.6 x 3.6 x 2 inches) W x H x D body only

Weight: 610-621g (1lb 6oz) without lens.

Product number: 231; 23100 (from 10/1966); 23102; 23104

Evolution of the Asahi Pentax Spotmatic:

The Pentax SL, introduced in 1968, was basically a Spotmatic without a built-in metering system, A replacement for the Pentax SV/H3v, it doesn’t have a battery compartment and is thus lighter than the SP. It was available in 3 variant, black and chrome Asahi, black Asahi, and black and chrome Honeywell.

The Asahi Pentax SP500 and SP1000 were entry level versions of the Spotmatic, the numerical suffixes reflecting their top shutter speeds. They had no self-timers, and were offered with the 55mm f/2 Super-Takumar lens with fully auto diaphragm. The SP 500 was introduced after the SP II in 1971, and the SP1000 after the SP-F in 1974. Dimensions: 143 x 92 x 50mnm (5.6 x 3.6 x 2.0 inches) body only, Weight: 600g without lens.

The Spotmatic SP II of 1971 had minor improvements to the Spotmatic’s metering system and film transport, was fitted with a hot shoe, had a FP and X sync flash switch under the rewind crank, and had film speed settings to ASA 3200. It coincided with the introduction of Super Multi Coated Takumar lenses that improved image quality and contrast, and had mechanical pins for aperture input to the metering system. Dimensions: 143 x 92 x 50mm (5.6 x 3.6 x 2.0 inches), body only; weight 625g (1 pound, 7 ounces) without lens. The SP IIa is essentially the same camera but added an “electric eye” to support dedicated Honeywell Strobonar772 and 882 electronic flashes.

The Asahi Pentax ES (Electro-Spotmatic) of 1971 was the first Pentax with an electronically controlled focal plane shutter (marked for speeds of 1-1/1000 sec, but capable of getting down to 8 sec) in aperture-priority mode, plus manual mechanical speeds from 1/60 to 1/1000 sec. It was the first Pentax to provide open-aperture when using SMC Takumar lenses, it’s powered by an SR-44 6-volt silver oxide battery, and it was available in chrome or black.

The Asahi Spotmatic F (SP-F) introduced in 1974 is my personal favorite of all the metered M-42 mount Pentaxes. It was the first match needle Spotmatic to offer open aperture metering using the updated Super Multi Coated Takumar lenses with an aperture position linkage to the camera, The SP-F has a third meter cell which acts as a switch when there’s no light, so it’s important to keep the lens cap on when the camera is not in use. The battery was changed to the now defunct PX625 mercury cell, but the meter circuit will accommodate current 1.5v silver oxide call without modifications, a big plus.

Sp_f_blk.jpg
My favorite Spotmatic combo: The Pentax Spotmatic F in black with the stellar 50mm f/1.4 SMC Takumar, one of the best 50mm f/1.4s ever!

Aside from specialized motor drive and data back models final standard M-42-mount Pentax was the Asahi Pentax ES II of 1973. Improvements to the ES include a shutter release lock (which provides a T setting when the shutter is set to B), interior viewfinder blinds, exposure compensation settings, and (official) shutter speeds from 8 sec to 1/1000 sec inn auto mode. Power is supplied by four currently available 1.5v alkaline or silver-oxide cells, it was available in chrome or black finish, and a special MD (Motor Drive) version was available.

Pentax ES II.jpg
Pentax ES II: Last and best of the autoexposure M42-mount Pentaxes, this one is fitted with the outstanding 50mm f/1.4 SMC Takumar lens.

All screw mount Asahiflexes and Pentaxes are beautifully proportioned, extremely well made, and, in the right hands, capable of outstanding performance. Their crowning glory is their robust, reliable construction and their Takumar lenses, renowned for their outstanding imaging performance and gorgeous rendition. The icing on the cake is that many if these cameras, especially the Spotmatic models, are readily available, outstanding values on the used camera market, and superb user collectibles for anyone wanting to experience the joys and challenges of analog photography. Try one with the stellar 50mm f/1.4 Takumar (any version, but especially the SMC) and I personally guarantee you won’t be disappointed.
 
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Thank you Jason, another great read.

Probably eight years ago or so, I stumbled across a close-to-mint black Spotmatic II with a 50/1.4 lens. It was at an antiques show and was sitting in the middle of a sea of black, plastic Point & Shoots on one table. The guy wanted $35.00 for it. I normally haggle, but not this time. I paid him the $35.00 and happily left. Later on, I learned that the 50/1.4 was the legendary 8-element version Asahi made for awhile. The camera works perfectly, even the meter. I use it when in the mood.

Jim B.
Good going! I bought my Spotmatic with 50mm f/1.4 Super-Multi-Coated Takumar years ago for about the same price, but it has the 7-element version of the lens. You can spot the (slightly sharper, smoother rendition) 8-element version by its IR mark on the DOF scale located to the right of the numeral 4 and it’s protruding rear element when you turn the focusing ring to infinity.
 
Pentax 85/4.5 Ultra-Achromatic Takumar, corrected for UV through to near-IR.



This lens is rare, was $1400 or so when new ~1970.
Nice! The 85mm f/4.5 Ultra-Achromatic Takumar is indeed a rare and awesome lens. I'd spring for one myself-except that they currently go for about $5K to $7K apiece in pristine condition!
 
Amazing what Pentax got up to back up n the day.

Indeed. They produced some amazing optics back in the day.

I sometimes wonder what might have happened if Pentax had introduced the K mount at the same time as the Spotmatic instead of sticking with the M42 screw mount for another ten years. Not that I think there is anything wrong with M42, but I think if Pentax had done so, they would have been in an even stronger position to compete against Canon, Olympus, and the other Japanese manufacturers and might have taken that strong second place spot behind Nikon in SLR cameras instead of Canon.
 
Indeed. They produced some amazing optics back in the day.

I sometimes wonder what might have happened if Pentax had introduced the K mount at the same time as the Spotmatic instead of sticking with the M42 screw mount for another ten years. Not that I think there is anything wrong with M42, but I think if Pentax had done so, they would have been in an even stronger position to compete against Canon, Olympus, and the other Japanese manufacturers and might have taken that strong second place spot behind Nikon in SLR cameras instead of Canon.
I'm not sure Pentax "might have been in a strong second place behind Nikon," but I agree they probably would have been in a stronger competitive position if they had switched to the K mount earlier. The M42 mount was a fine idea when Praktica introduced it in the '30s, and it became a de facto "universal" mount in the '60s, but bayonet mounts are superior in many ways, including speed of lens changing and precise positioning of mechanical couplings.
 
Very interesting article. Thank you for sharing! I am very much looking forward to reading more of your "The Pentax Papers". Hopefully you will cover the 645 and 6x7 medium format systems.
Thanks for your kind words. I'm currently researching Part 2 of the Pentax papers, which will cover the K-mount 35mm models. I'll eventually get around to covering the Pentax 645 and 6x7, but probably not until late fall or early winter 2024. Stay tuned.
 
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