Pentamatic SLR & the Move to M42

Contents

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Pentamatic Development
Pentamatic Arrives

The Lens Problem
Other Design Issues
f/1.8 5.5 cm Standard Lens
Price Comparison USA Market
Expert Critical Evaluation

Pentamatic II
Pentamatic S
Penta J, Reflex 35 & the M42 Line
R.I.P.
Pentamatic/Pentamatic II Shutter Button Variation
Pentamatic Lenses

Tomioka Tominon Normal Lens & 10 cm Mystery Lens
Accessory Lenses

Pentamatic Accessories
M42 Mount Mystery
Claims of Zunow Sourced 35 mm Lenses
A Mamiya Twist
Serial Numbers & Production
Pentamatic & Related Links

Pentamatic Development

Until 1957, Yashima was a company building TLRs based on the Rolleicord design. Not much had changed since 1953 even though there were a lot of models. The variations mostly involved bought in shutters and lenses and how they were mixed and matched. Any improvements had been evolutionary rather than revolutionary. In that context, it is hard to imagine that the company had a large design and engineering staff, let alone one experienced in cameras other than TLRs. Yet from 1957 to 1960, Yashima/Yashica released the Yashica 8 movie camera followed by derivative models, Yashica 35 fixed lens rangefinder camera followed by derivative models, the Y16 sub miniature camera and its first SLR, the Pentamatic. It also managed to design and build three brand new 44 models. How was that all possible?

By way of background, the Nikon F, released in April 1959, was an outstanding professional level camera from the outset but its development had evolved from the existing 1957 Nikon SP rangefinder model with the main new parts being the mirror box, pentaprism viewfinder and bayonet mount. The Mamiya Prismat CLP released in 1960 had been eight years in development since the first Prismflex prototype in 1952. Designing an SLR from ground up in a little over two years and solving the engineering problems along the way, not to mention tooling up for a new type of camera and working with your lens partner(s) to develop a new range of lenses, would have been quite a challenging task for Yashica.

How the Pentamatic and other new models were developed is unknown but we can speculate that maybe Yashica had some assistance. It acquired Nicca Camera and its engineers in May 1958 so it had access to the basic structure of a focal plane shutter 35 mm camera and the people to develop it further. There was certainly Tomioka, Yashica's TLR lens supplier, whose Tominon brand appears on some of the Pentamatic accessory lenses and is believed to be responsible for at least the f/1.8 5.5 cm standard lens, if not perhaps the f/1.7 5.8 cm on the Pentamatic II. It is possible that Yashica also used the services of Konan Camera Laboratory, its technological partner for the Yashica Future 127 project in the same 1957 to 1959 time frame. The wild card is Zunow Optical Industry Co., Ltd.

In development since 1956, Zunow launched its SLR in 1958. Its features pre-empted the Nikon F and included a removable pentaprism and a very significant world first, a fully automatic aperture diaphragm. Unfortunately, Zunow was too small a company to properly bring such a complex design to market and relying on many outside suppliers resulted in crippling quality issues and probably only 500 cameras or so were produced before the project collapsed. It is a little known fact that Zunow was Yashica's original cine lens supplier for the Yashica 8 movie camera and it may have supplied all the turret mount lenses (the name “Yashinon-V Zunow” still appears on the T3 lenses released in 1959). Further below is some speculation about Zunow's role with two 35 mm lenses. Did the cooperation extend further and Zunow contribute to the semi-automatic/ automatic diaphragm design of the Pentamatic cameras, or any other aspects? The possibility is certainly there but I stress, there is no actual evidence. It should be noted that Yashica's claimed acquisition of the bankrupt Zunow happened in January 1961, i.e. after the release of the Pentamatic and Pentamatic II.

Some Japanese bloggers see similarities between the appearance of the Zunow and Pentamatic but the reality is that the shape of the pentaprism is like, well like a pentaprism and is somewhat shared between the Zunow, Pentamatic and Nikon and the Nikon is certainly not related to the other two. Also, the front mounted shutter button of the Zunow and Pentamatic is found on other cameras too such as the Contax S and various Praktica and Miranda models. On the other hand, there are some similarities with the cosmetics of the Zunow lenses and the Pentamatic ones. Co-operation, inspiration or coincidence?

(Image of f/1.2 lens option from larger advertising brochure)

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Pentamatic Arrives

The original Pentamatic was actually a handsome, up-to-date, modern looking mid-spec camera, a little late but not too late to market. In the 24 April 2004 edition of the well regarded UK magazine Amateur Photographer, regular columnist Ivor Matanle calls it “by any standards a fine piece of engineering”. In his autobiography, the famous Weegee, Arthur Fellig, also commented favourably on it. The Pentamatic was keenly priced for its spec level but certainly not a bargain either. It featured an instant return mirror and non-rotating shutter speed dial with 1/1000 but its defining feature is the shoulder mounted accessory shoe - most contemporary SLRs were sans shoe, offering an accessory clip-on type instead. A three position lever on the back allows the rewind crank to pop up and the back to be opened:

Together with the Mamiya Prismat CLP, it followed the 1959 Canonflex, Nikon F and Petri Penta releases which joined Miranda (Orion Camera Co.), Asahi Pentax, Firstflex (made by niche maker Tokiwa Seiki, also responsible for the 1955 Pentaflex with porroprism viewfinder), Topcon and Minolta Japanese made interchangeable lens pentaprism SLR models. The revolutionary Zunow had already been and gone.

The release date for the historically rather important Pentamatic is contentious. Occurrences on the net are roughly divided between 1959 and 1960 with perhaps 1959 favoured, usually in conjunction with the word, “introduced”, however, there is another claim of a “Yashica/Kyocera sourced” date, March 1960. The Trademark filing date in Japan was 18 September 1959 and in the US, it was 12 February 1960. The official Kyocera Optec website of today lists Tomioka SLR lens production as commencing in 1960. Contributor Chris Whelan believes that he has decoded the Pentamatic serial numbers, with which I concur, and that the camera in the English language user manual is from December 1959, almost certainly a pre-production example. Series production seems to have commenced in January 1960. Release could have happened at any point from then on.

An article by Hiroshi Sugawara in Japanese “Camera Collectors' News” of November 1999 claims that the Pentamatic was released in late January 1960. That would be in Japan. He also seems to make the point that it was common practice amongst Japanese camera makers at the time to announce their new cameras two or so months before the actual release which he takes to mean the first shipments to camera stores. That would make the initial announcement in October, maybe November 1959. Unfortunately, specifics are not provided.

Meanwhile in the USA, page 48 of the Philadelphia Inquirer newspaper of 4 May 1960 contains an ad placed by Yashica which tells us that the new Pentamatic, and also the new Yashica Mat-LM (plus some others), can be seen at the Delaware Valley Photo Show, or “at your local Yashica dealer”, and this was “their first public showing” after the “introduction at the trade show in St. Louis” (note, the linked ad has been edited for easier viewing). According to Chris Whelan, this was “the 36th annual trade show of the Master Photo Dealers & Finishers Association convention in St. Louis, held March 21-25, 1960.” So announced late 1959, released in Japan in January 1960 and in the USA in March-May, depending on definition of “release”.

The original model is the only one with evidence of worldwide sales and advertising. Chris Whelan and I have found ads and/or brochures from Japan, USA, Germany, France, Singapore and Australia. Although most Pentamatics found for sale or sold on auction sites are from Japan and the US (probably the highest number), quite a few are from the UK.

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The Lens Problem

Nearly every reference source implies that the Pentamatic's “proprietary” bayonet lens mount was an impediment to the camera's sales success. Well, yes, but what has to be understood is that every successful bayonet lens mount, including the Nikon F mount, was/is “proprietary” and were usually accompanied by an ever increasing selection of matching lenses designed for the system. In 1960, the M42 screw mount was far from “universal” yet with the main users being the East German Praktica and the Japanese Asahi Pentax with smaller West German brand Edixa and East German Contax (VEB Zeiss Ikon/Pentacon) already declining. However, the problem for Yashica was threefold; the lack of lenses on release, slow development of it's lens portfolio and the lack of automatic lenses.

Much was made of the camera's automatic aperture diaphragm stop down ability but only the standard f/1.8 5.5 cm lens was “automatic” and even that was a marketing stretch - yes, the aperture diaphragm automatically stopped down at the time the shutter was released but the return of the aperture diaphragm to fully open for viewing was only accomplished by cocking the shutter again. At best, a compromise between fully “automatic” and manually cocked “semi-automatic” lenses, although admittedly state of the art only a year or two earlier on the 1958 Minolta SR-2 and some of the German models, but cameras such as the Zunow and Nikon F had already set the standard with others following. As noted below, the rare and short-lived Pentamatic II did feature a fully automatic aperture.

More than anything else, an SLR is defined by its lenses. Initially, according to the user manual, only two accessory lenses were offered, an f/2.8 35 mm moderate wide angle and an f/2.8 100 mm short/medium telephoto and both of these were of the manual pre-set type:

(User manual scan courtesy of Chris Whelan)

This minimalist selection, without even a hint of more to come, must have set some sort of record for interchangeable lens SLRs and undoubtedly would have been a real disappointment for photographers who were looking to SLRs to extend their focal length reach over the limitations imposed by interchangeable lens rangefinders, for example. In comparison, when the small lens maker Zunow introduced its first SLR in 1958, it advertised four fully automatic lenses with another four pre-set types planned (three longer, up to 800 mm, and a macro). Admittedly, perhaps only three of the lenses were ever produced before the project folded but the point is that Zunow understood the importance of making available a range of lenses to meet customers' needs.

By June 1960, an f/2.8 135 mm was added and a subsequent system brochure also includes an f/4 250 lens. The Pentamatic II user manual, with a launch around September 1960, added a fifth lens, an f/3.5 180 mm. When the Pentamatic S and first M42 models were released near the same time, a completely new set of lenses available in both Pentamatic and M42 mounts were advertised in focal lengths up to 400 mm (details below), but still no wider than 35 mm. In comparison to major competitors, still a limited range. Incredibly, given the ability of the camera, they all remained pre-set types. Note, all the lenses were marked in “cm” but advertised in “mm”, which makes writing about them difficult. I have mostly gone with what is marked on the lens.

So either Yashica chose to not develop accessory lenses with automatic diaphragms for some management reason, or there were technical issues still to overcome with the implementation. Unfortunately, we don't know how Yashica's external lens supplier(s), assumed to be Tomioka in the main or exclusively, fitted in. As noted above, Tomioka had not produced SLR lenses previously, and possibly not interchangeable rangefinder lenses either (the relatively low volume YE and YF lenses are unknowns and at least one of the telephoto lenses was made by someone else). These required relatively complex machined barrels plus the addition of aperture diaphragm mechanisms, not to mention the “automatic” aperture of the standard lens, compared to the threaded tubes of TLRs and usually simpler leaf shutter viewfinder/ fixed lens rangefinder cameras that were Tomioka's bread and butter at the time. Like Zunow before it, Yashica did offer adaptors for Praktica M42 screw and Exakta bayonet mount lenses right from the beginning (already featured in the user manual) but these were manual operation only and like Yashica's own preset lenses, they could not use the camera's headline automatic aperture stop down feature that customers were paying for.

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Other Design Issues

Compared to competitors, two other annoying quirks that were likely due to cost cutting were, when loading film, the need for manual frame reset with an easy to accidentally move toothed wheel and the lack of a self-timer (bizarrely, the user manual shows the use of a Walz branded accessory timer - finally rectified in the S model).

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f/1.8 5.5 cm Standard Lens

This lens is comprised of 6 elements in 4 groups (schematic in Pentamatic S brochure). The filter size is 52 mm and conveniently, all lenses for the Pentamatic are claimed to be the same (note, as implied by the Pentamatic II user manual in regard to the 54 mm slip-on lens hood, that may only apply to the first lenses, the 3.5 cm and 10 cm, besides, I doubt that both the 13.5 cm f/2.8 and f/3.5 are the same as each other and it is certainly not the case with the black nose lenses released with the Pentamatic S - see Pentamatic Lenses below). The number of aperture diaphragm blades is either 6 or 9. There are three main serial number ranges, the earliest starting with 5910 and 5912 and the last with 605. Strangely, an early lens, owned by contributor Chris Whelan, with serial number 59100092 features 6 blades, however, slightly later lenses, 591001xx and 591005xx, feature 9 blades as seem to all lenses with serial numbers beginning with 5912. Lenses beginning with 6050, 6051 and 6052 (the majority and also including all original fitments for the Pentamatic S) are back to 6 blades.

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Price Comparison USA Market

The table below provides some 1960 and 1962 prices in the US plus key specs of comparative Japanese SLR models. Note, from serial numbers, it looks like the last Pentamatic was made in January 1961. By February 1962, the last examples were being advertised in Modern Photography at the fire sale price of $94.50, therefore the August 1962 Popular Science table is certainly out of date.

Camera
Max.
f/stop
Max.
Shutter
Lens Range
Exposure
Meter
Price
From Popular Science, August 1962
Nikon F
f/2
1/1000
28-1,000 mm
No
$329.50
Cannonflex RM
f/1.8
1/1,000
35-1,000 mm
Yes
$300.00
Topcon C
f/1.8
1/1,000
35-1,000 mm
No
$295.00
Miranda Automex
f/1.9
1/1,000
28-400 mm
Yes
$299.95
Miranda DR
f/1.9
1/500
28-400 mm
No
$169.95
Minolta SR-3
f/1.4
1/1,000
35-600 mm
No
$229.50
Minolta SR-1
f/1.8
1/500
35-600 mm
No
$179.50
Pentax H3
f/1.4
1/1,000
35-1,000 mm
No
$199.50
Pentax H1
f/1.8
1/500
35-1,000 mm
No
$149.50
Pentamatic
f/1.8
1/1,000
35-400 mm
No
*$159.95
Adapted From Modern Photography, February 1960
Minolta SR-1
f/1.8
1/500
35-600 mm
No
$249.50
Pentax H2
f/2
1/500
35-1,000 mm
No
$179.50
Pentamatic
f/1.8
1/1,000
35-100 mm
No
*$159.95

* advertised as $159.95 plus $15 for the ever ready case, total cost $174.95

An Olden Camera Co., New York, ad for the Mamiya Prismat NP released in February 1961 advertised it at $118.50, illustrating what a bargain price might look like. The top speed of 1/1,000 and Canon Exakta mount f/1.9 lens made it competitive. Like Yashica, Mamiya was trying to break into the 35 mm SLR market - this was the company's second model.

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Expert Critical Evaluation

The November 1999 “Camera Collectors' News” article by Hiroshi Sugawara, mentioned above, makes reference to the June 1960 edition of Japanese magazine “Asahi Camera” which reported on the results of a disassembly, inspection and testing of a Pentamatic in its camera assessment lab. This was jointly undertaken by celebrated Japanese photographer Mr Ihei Kimura, Professor Jun Koizumi from Tokyo University and camera repair technician Mr Tsui Uchida Yukichi.

By way of background, Hiroshi Sugawara explains that in Japan at that time were the high-end SLRs, such as the Nikon F and Canonflex, costing 60,000 yen or more and the middle class SLRS around 30,000 yen (the Pentamatic ads price it at 34,800 yen plus 2,000 yen for the ever-ready case). This is where He places the Pentamatic but “one step higher” because of the 1/000 shutter (in comparison to those models with 1/500 shutters). He also notes that the camera was advertised as being able to use other mount interchangeable lenses by use of dedicated adaptor rings but a consequence of this design was a short flange to film plane distance necessitating compromises with the mirror size and mechanism, an aspect which elicited negative comment by the review team.

Testing by Asahi Camera indicated “that the mirror position slightly deviates before and after cocking” so that it was necessary to focus after cocking the shutter (advancing the film). Other comments included that “there is no consideration to attach a dioptre correction lens to the eyepiece, the view field ratio is slightly narrower than the range actually seen on the film...that the internal reflection of the body is quite large, the film screen spacing is irregular... (the) slow shutter speed governor worked poorly... the manual film counter moved (too) easily, the mirror is small, the mirror is small even with the standard lens.”

On a positive note, “the pentaprism is firmly fixed to the body with springs from both sides, a metallic protective plate is attached to the top of the pentaprism... die casting of the body is good in finishing accuracy”. There is also reference to “the focal plane shutter made by the Nicca engineers”, I'm not sure in what context but certainly positive and also confirming the importance of the Nicca acquisition to the project. However, the top speed of the shutter tested slow at 1/700 but the 1/500 and 1/250 speeds were accurate.

The lens was also assessed, “Tomioka Optical made Auto Yashinon 55 mm f/1.8 (4 group 6 element type) has a large opening efficiency of 65%, the resolution is excellent, but the lens barrel is too heavy. Focusing is from infinity to 0.5 m.” Testing found ghosting with bright point light sources, particularly at night. A problem was found with the aperture blades which would not fully open beyond f/2, perhaps this was a reason for the change from 9 aperture blades to 6?

The report noted that the body and lens both featured “advantages and disadvantages intermingled.” This appeared to continue with quality as well with the report noting that whilst “screws inside the camera may well be done, but from the point that scratches are attached to the grooves of some screw heads, etc., non-experts are mixed in the assembly,” i.e. semi-skilled labour was being used. “There are also some strange things in the way of cutting the teeth of gears.” “As a result of first-class and second-class products living together,” either the report, or Hiroshi Sugawara, notes that there is sometimes a feeling of coarseness, or as the translation puts it, “sometimes the whole sort of something is jerky.”

Finishing off, Hiroshi Sugawara comments that the front mounted shutter button is easy to use and in his view, helps with reducing camera shake, but importantly, he notes that in Japan it was not popular and it was not a “hit” with Topcon, Miranda or Petri either.

So what does this evaluation by Hiroshi Sugawara and the Asahi Camera team mean? There was both good and bad. For a first completely new camera type from a maker, not just a new model, there was plenty of good with some opportunities to improve, nothing disastrous. Any product is a compromise between features, quality and price so the only meaningful way for us to make an assessment is look at how this review compares to similar reviews of the Pentamatic's competitors. I'll be keeping a lookout.

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Pentamatic II

A Pentamatic II featuring fully automatic aperture operation and a different f/1.7 5.8 cm standard lens with depth of field stop-down button (and slider to re-open the aperture) and 10 bladed aperture diaphragm (more lens details further below in A Mamiya Twist) was released around September 1960 and by serial numbers, seems to have been produced alongside the original Pentamatic until only January 1961 when production of both ended:

The fully automatic aperture stop down and opening is controlled by the camera and also works with the earlier f/1.8 5.5 cm lens (I have tested both).

It seems to have only been advertised in Japan and all found examples are from Japanese auctions and websites. A Japanese brochure featuring both models advertises the Pentamatic at ¥34,800 plus ¥2,000 for the ever ready case and the Pentamatic II at ¥37,300 plus ¥2,200 for the case. The fact that it lasted barely four months and didn't make it out of Japan suggests that there was a management decision about the future of the series, an inherent design or reliability problem, or that there was a lens supply issue as suggested further below. Yashica was not a niche player and a completely new high quality lens would have come at some cost and is very odd to have been abandoned so quickly.

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Pentamatic S

Both the Pentamatic and Pentamatic II were replaced by the Pentamatic S in early 1961, although unsold stock of the Pentamatic appears to have lasted into 1962. There is a claimed release date of May 1961, from serial numbers, series production seemed to commence in April so that would fit. The S reverted to the original less than fully automatic aperture, requiring the shutter to be cocked to open the aperture, and standard f/1.8 5.5 cm lens with 6 aperture diaphragm blades found on the Pentamatic but added a split-prism rangefinder focusing aid, self-timer and an external exposure meter mounting plate and shutter coupling key-way:

Because of the self-timer positioning, the shutter button was now horizontal.

Most found examples are from the US with a small number from Japan (four plus one box bought by contributor, aficionado and collector Chris Whelan). Even so, one Japanese blogger claims that the model was for export only and no Japanese ads or brochures have been found by Chris. He has one US system brochure for it and another where it appears with the Penta J and J-3 M42 models. There was an ad for the camera run at least twice, once in Popular Photography (page 90, date unknown) and the second in an unknown publication (it adds a Canadian distributor's address) and it also appears with other Yashica cameras in the 14 January 1962 edition of LIFE magazine. The article in Japanese “Camera Collectors' News” of November 1999 referred to further above is about the Pentamatic models but only mentions the original and the Pentamatic II so perhaps the Pentamatic S was only released in the US and the examples found in Japan have been returned by collectors, apparently not an uncommon event, and perhaps by military personnel as they moved to and fro and traded/upgraded gear.

The “S” could stand for Split-prism rangefinder focusing (according to a Japanese blogger, suggested in an unnamed book), Shutter coupled exposure meter, Self-timer, all three or something else entirely. Yashica's US brochure and ad concentrate on the ease of focusing (shared with the Penta J below).

The Japanese user manual for the Pentamatic II mentions the availability of five accessory lenses but the English language Pentamatic S manual reuses the page from the original Pentamatic manual and therefore implies that apart from the standard lens, the additional lenses available are limited to the original 35 mm and 100 mm! In fact, even that was incorrect, the accessory lenses for the Pentamatic and Pentamatic II were completely replaced by an entirely new set, see Pentamatic Lenses below.

The US price was “under $200 plus case”, so a premium of $40 over the original model, not exactly cheap for the specification. The clip-on exposure meter was $25.

The last example in my database is from March 1962.

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Penta J, Reflex 35 & the M42 Line

The first M42 model, the Penta J, was released in 1961 already (production starting in June and a claimed release in September), indicating a degree of panic and lack of commitment to fixing whatever the issue(s) with the Pentamatic was/were. In markets outside of Japan and USA, it was usually known as the “Reflex 35” even though the “J” is still on the exposure meter mount. The only specification differences between the two are that the Penta J has a split-image rangefinder as a focusing aid and the Reflex 35 uses microdots and initially, the Penta J used a film speed reminder dial in ASA only up to a maximum of 200 ASA and the Reflex 35 used a combined ASA/DIN dial up to a maximum of 800 ASA. This dial was adopted on later examples of the Penta J also.

Although similarly styled to the Pentamatic models and still solidly built, the Penta J cut costs by reducing the maximum shutter speed from 1/1000 to 1/500, dropping the newly added self-timer and the faux-automatic lens aperture in favour of a manually cocked semi-automatic set-up styled along earlier Asahi Pentax lines, increasing the maximum lens aperture to f/2 and of course, changing from the bayonet mount to M42 mount. The shoulder mounted accessory shoe was also dropped and the complicated film rewind and back opening mechanism was simplified. It retained the ability to fit the external exposure meter of the Pentamatic S but the Penta J version's piggy back shutter speed dial is limited to the camera's 1/500 speed:

This is an early example. Note the Pentamatic and Pentamatic II style strap lugs, soon replaced by the Pentamatic S style lugs, and the black filled in “J”, also changing to a plain outline early on. Note also the gold filled “Penta” which later changed to black (very hard to track in photos). In contrast, below is a late Yashica Reflex 35 (all found examples look the same):

The name “Penta” makes sense as the aperture diaphragm is now not automatically cocked so the “matic” has been dropped but what does the “J” stand for? Nobody is absolutely certain but the two known Japanese ads have ジャガー written across the “J”, meaning “Jaguar” (first identified for me by contributor Chris Whelan and also noted on several Japanese blog sites). Are the admen playing with us, or is that the real name, noting that the “Lynx” rangefinder was released in 1960?

The Penta J was followed in late 1962 by the J-3 with built-in CdS exposure cell below the rewind crank, re-instated self-timer and shutter button on top of the camera. A US brochure from the end of 1962, or beginning of 1963, features the Pentamatic S, Penta J and J-3 together.

As far as I can tell from various sources and also serial numbers, the other M42 cameras followed in this order: J-5, J-P, J-4, TL Super, J-7, TL, TL Electro-X, TL-E, TL Electro-X ITS, TL Electro, Electro AX and FFT. There was also a TL Super rebadged as a “Porst Uniflex 1000s” for a West German distributor and US department store, Montgomery Ward, offered two Yashica based models under its own brand. These appear to be specials using an amalgam of parts. The first was the “Wards SLR 500” which seems to be based on the J-P with its distinctive CdS meter mount but without the self-timer and the film advance lever replaced by the Penta J type with manual counter reset. The “Wards SLR 600” seems to be based on J-7 (or more probably, the uncommon J-4 - same body but 1/500 top speed) but retains the Penta J film advance. I haven't seen the 500 lens but the 600 uses a cosmetically updated version of the Penta J manually cocked semi-automatic f/2.

The “J” bodies were one related family style-wise with evolving Pentamatic design cues and CdS exposure meters, if fitted, were externally mounted like the J-3. The rest belonged to the later, more angular bodied “TL” group and featured TTL, or through-the-lens, metering. TL Electro-X featured below:

With the release of the Contax RTS and advent of the Contax/Yashica bayonet lens mount in 1975, production of remaining M42 models ceased except for the lower spec TL Electro which seemed to soldier on until 1978 or so, perhaps as an entry level model and/or to keep faith with existing M42 customers.

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R.I.P.

In the US brochure, the Pentamatic S was advertised at “under” US$200 and the Penta J, at “under” US$130, firmly back in the more budget mass market territory that Yashica was familiar with (the original Pentamatic had been advertised at US$159.95). The ensuing models remained well built but were comparatively ordinary until perhaps the late 1960s TL Electro-X with electronically controlled shutter. Sales were also relatively lack-lustre.

To me, it seems as if the Pentamatic was designed by engineers who understood what was necessary to compete in the SLR market as it was developing but that it didn't really fit with the TLR marketing strategy that made Yashica successful - high volumes at low margins through good quality at prices that others could not match. With other new products at this time, this still seemed to be management's guiding principle whereas the Pentamatic was somewhat in the middle with specs and the price, whilst good value, was not a bargain. And of course, there was also the worst lens availability of any comparative model. There was no pretense of professional aspirations but it seemed to be developed with enthusiasts in mind whilst perhaps management was looking for a product for the mass market consumer. To some extent, this is reflected in the advertising material which continued to focus on the value aspect and is rather lacking in technical interest, as are the English user manuals, compared to other brands hungry to get their models noticed by “photographers”.

The Pentamatic was not perfect but certainly seemed to have promise which was not realised for one reason or another.

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Pentamatic/Pentamatic II Shutter Button Variation

Eagle-eyed correspondent Tom Chandler has alerted me to a shutter button variation missed by both Chris Whelan and myself. Sometime between September (when the Pentamatic II was released) and October 1960, the angled shutter button mounting platform was changed on both the Pentamatic and Pentamatic II to make the button slightly less vertical. The platform itself is also slightly different and more substantial with a larger diameter to the cylindrical part under the button. Early Pentamatic on left, late Pentamatic II on right (photographs chosen for convenience, I have examples of both models with early and late button mounting platforms):

To make a change this early on with only low production volumes suggests some sort of issue rather than just a minor ergonomic improvement, if it is that.

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Pentamatic Lenses

As noted earlier, only the 5.5 cm f/1.8 and 5.8 cm f/1.7 standard lenses were pseudo-automatic/automatic (depending on body), all the accessory lenses were of the pre-set type. The table below lists the lenses by focal length which is also pretty close to the chronology of the original lenses. The accessory lenses are split into two separate groups; the silver nose (what we might call “first series”) released progressively with the Pentamatic and Pentamatic II and the black nose (what we might call “second series”) released with the Pentamatic S and first M42 models and which in Pentamatic mount completely replaced the first series.

Focal
Length
Aper-
ture
Filter
Size
Lens Name Serial
Numbers
K.C.
(red)
Comments
Standard Lenses
5.5 cm
f/1.8
52 mm
Yashica Auto Yashinon
(6 aperture blades)
59100092
-
1 only, earliest standard Pentamatic lens
found in the wild (Chris Whelan)
5.5 cm
f/1.8
52 mm
Yashica Auto Yashinon
(9 aperture blades)
5910xxxx &
5912xxxx
-
2 series, standard Pentamatic lens until
about May 1960
5.5 cm
f/1.8
52 mm
Yashica Auto Yashinon
(6 aperture blades)
605xxxxx
-
Standard Pentamatic & Pentamatic S lens
5.5 cm
f/1.8
52 mm
Tomioka Tominon
600xxx
-
1 only, found with earliest Pentamatic S,
possibly not production lens
5.8 cm
f/1.7
52 mm
Yashica Auto Yashinon
424xxx to
595xxx
-
Standard Pentamatic II lens, continuous
serial number range with big gaps
Accessory Lenses - First Series, Silver Nose, Pentamatic Mount Only
3.5 cm
f2.8
52 mm
Yashica Tominon Super
Yashinon-R
350xxx &
364xxx
-
Two serial number ranges
10 cm
f/2.8
52 mm
Yashica Super-Yashinon
591xxxx
-
1 only, found with Tomioka Tominon
10 cm
f/2.8
52 mm
Yashica Tominon Super
Yashinon-R
100xxx
-
13.5 cm
f/3.5
?
Yashica Super Yashinon-R
1350xxx
K.C.
13.5 cm
f/2.8
?
Yashica Super Yashinon-R
1328xxx,
1355xxx
K.C.
1 only1328xxx lens, rest 1355xxx
18 cm
f/3.5
?
Yashica Super Yashinon-R
180xxxx
K.C.
Relatively rare
25 cm
f/4
?
Yashica Super Yashinon-R
250xxxx
K.C.
Accessory Lenses - Second Series, Black Nose, Either Pentamatic or M42 Mount
3.5 cm
f/2.8
46 mm
Yashica Super Yashinon-R
28xxxx
-
All serial numbers start with “28”
13.5 cm
f/3.5
40.5 mm
Yashica Super Yashinon-R
1351xxx
-
13.5 cm
f/2.8
55 mm
Yashica Super Yashinon-R
1380xxx &
1351xxx
-
1 only 1351xxx lens, similar number to
f/3.5 version
20 cm
f/4.5
43 mm
Yashica Super Yashinon-R
200xxxx
-
So far, only in brochure and M42 found
30 cm
f/5.5
43 mm
Yashica Super Yashinon-R
30xxxx
-
6 digit number
40 cm
f/6.3
43 mm
Yashica Super Yashinon-R
400xxxx
-

 

The accessory lenses mostly use the focal length as the prefix for the lens serial number. The main exceptions are the second range of the first series 3.5 cm f/2.8 Yashica Tominon Super Yashinon-R which begin with “364”, the second series 3.5 cm f/2.8 Yashica Super Yashinon-R (uses aperture instead) and the one example of the 10 cm Yashica Super-Yashinon which uses a number similar to the standard lens format and is presumed to be an early type but was found with the Pentamatic S and Tomioka lens below. The first series 13.5 cm f/2.8 lenses mainly feature the focal length in the format of “1355xxx” but there is one early exception, 1328xxx, and the second series starts with 1380xxx but then seems to change to 1351xxx, i.e. the same as the second series f/3.5 type (I have double and triple checked all details).

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Tomioka Tominon Normal Lens & 10 cm Mystery Lens

The one 5.5 cm f/1.8 Tomioka Tominon found with the earliest Pentamatic S (with very low pre-production like number believed to be made in February 1961 when the very next camera is from April when series production seems to have started) is a complete mystery. There is no way of telling whether it is original to the camera.

(Detail from larger web images)

The ribbing on the focusing ring is not continuous like on the other standard lenses and earlier (most) accessory lenses and is most commonly found on the later longer focal length lenses. Whereas some of the accessory lenses feature the “Tominon” name, it is the only Pentamatic mount lens where the “Yashica” brand is replaced by “Tomioka” suggesting that it is not a Yashica marketed production item. This lens could have been testing the ribbing on/for the standard lens but it could also be an even earlier prototype of the standard lens from before the Pentamatic release. If not a prototype of some type, then I would presume a Tomioka initiative to sell a replacement spare. Also found with this set is the only 10 cm Yashica-Yashinon (only accessory lens example of any length without the “Yashinon-R” name) with odd 59100xx lens number which matches the number style of the first of the Pentamatic body numbers. (The two lenses and camera were for sale together on a Japanese auction site. It is possible, and even likely, that none of the items are directly related to each other in a timeline sense, the common denominator perhaps being that originally none of the items were possibly meant for retail sale. Yashica did go bankrupt and eventually Kyocera became the owner - at any point in the process, all sorts of stuff may have been sold off to pay down debt and “unnecessary” inventory etc.)

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Accessory Lenses

As alluded to earlier, there are two series of accessory lenses; the silver noses and the black noses. The silver noses have a distinct family similarity to the standard lens and most seem to be designed for the Pentamatic mount, the exception perhaps being the 25 cm which may have a replaceable mount of some type. The silver nose series were released gradually with the Pentamatic and Pentamatic II, only the f/2.8 3.5 cm and 10 cm lenses appearing in the first Pentamatic user manual (see further above). By the time of the Pentamatic II, there was nearly a full set to 25 cm in this Japanese ad or brochure, only the f/2.8 version of the 13.5 cm is missing but I have found several actual examples and it appears as one of the set of six available lenses in a US Pentamatic ad appearing in Popular Photography (date unknown):

(Scan courtesy of Chris Whelan)

Production of both the Pentamatic and Pentamatic II seemed to end abruptly in January 1961. When the Pentamatic S was released a few months later, the silver nose accessory lenses apparently disappeared as well. All of the found Pentamatic S brochures feature a new set of lenses from 3.5 cm to to 40 cm. These have black noses, different cosmetics and come in either Pentamatic or M42 mount. The mounts look to be easily interchangeable. The 10 cm length appears to be dropped, the 18 cm replaced by a 20 cm, the 25 cm replaced by a 30 cm and there is a new 40 cm. The page below is from a Yashica lens brochure featuring both mounts:

(Scan courtesy of Chris Whelan)

The same lenses appear in this Pentamatic S system brochure, however, note that the picture and filter size (40.5 mm) for the 135 mm lens appears to be for the f/3.5 version of the lens (not otherwise mentioned), not the f/2.8 as it is named:

(Scan courtesy of Chris Whelan)

(Click on scan for PDF of complete brochure)

The 13.5 cm f/3.5 does appear in a later brochure featuring the Pentamatic S and Penta J and J-3 M42 cameras. That brochure also mentions a 90-190 mm zoom lens available in either mount.

I think that the first series and second series images in the brochures and the differing focal lengths and filter thread sizes (see table below) make it very clear that the lenses are not related. Several of the first series lenses have the “Tominon” name included and the slow release of lenses is consistent with Tomioka getting up to speed designing, tooling and making its first SLR lenses (in accordance with its own claims). The abrupt change of direction by Yashica seems to have resulted in recognition of the need for a longer lens as well as a desire for lenses to suit either mount and to be available immediately. I suspect that by this time, Yashica knew that the Pentamatic and its mount were on borrowed time and maybe the wholesale move of Pentamatic lenses to the interchangeable mount series was to allay the possible ill-will from people buying a lens for their Pentamatic only to be stuck with an unsupported mount in the future? Having designed one set which was completely different, did Tomioka design and make these too? I doubt it.

The 20 cm, 30 cm and 40 cm lenses are almost certainly Tele-Tokinas/Minetars made by Tokyo Koki Co., Ltd., later Tokina. Possibly also the 3.5 cm and 13.5 cm but I'm still searching for examples. The barrels were threaded with T-mounts (invented by Tamron) to which screwed various dedicated mounts such as M42, Pentamatic and quite a few have been found with Minolta mounts. These mounts were locked in place by set screws - changing a mount involved loosening the set screws, unscrewing the mount from the T-mount and then reversing the order with the new mount. Simple and no doubt something which appealed to Yashica with its new two mount SLR range. Below is the 20 cm Minetar version:

(Detail from larger web images)

Compared to the 20 cm Super Yashinon-R in the brochure, the only difference is that lens hood is unscrewed and the lens focus has been cranked out to a relatively near position instead of infinity. The bayonet mount type is unknown.

The Tokyo Koki Co., Ltd., maker name appeared on the Tele-Tokinas and Minetars but they were sold as various other brands as well, e.g. Lentar seems fairly common in the 20 cm size at least and also Hanimex. Once automatic diaphragms became popular, their proprietary actuating systems removed the attraction of the T-mount except for the most basic of lenses. Yashica then moved on to its new line of M42 lenses but interestingly, the 30 cm/300 mm version with T-mount from the above brochure still appears as a budget option to the auto version in the Yashinon-DX lens catalogue, which by now presumably featured mainly Tomioka made lenses again.

A little further above, I also mentioned a zoom lens appearing in a very late (for the Pentamatic) brochure. This is the Yashinon-R f/5.8 90-190 mm. The first zooms for still photography were just starting to appear at this time. A similar zoom appears in the Ricoh catalogue and as Tomioka was known to have made lenses for Ricoh as well as Yashica, some think that it is a Tomioka lens. Others have attributed it to Tokina. There were certainly plenty of brands using it. As well as Yashica and Ricoh, found examples include Beroflex and Polaris in M42 mount, Soligor in Canon FD mount and Upsilon in Minolta mount and Hanimex in an unknown bayonet. In all likelihood, the non-camera makers offered it in all common mounts and there are probably other brands as well. Some later versions feature an auto aperture - in the case of Yashica, the lens became an Auto Yashinon. By the time of the DX catalogue, it had been replaced by a new Auto Yashinon-DX f/4 80-160 mm zoom. My personal view is that the maker remains unknown - I have not seen any hard evidence, just opinions.

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Pentamatic Accessories

The available accessories noted in user manuals and brochures include Exakta bayonet and Praktica screw (M42) lens mount adaptors, extension tubes, bellows, microscope adaptor, right-angle finder, lens hoods, filters, copy stand and clip on exposure meter for the Pentamatic S (modified version without 1/1000 shutter speed available for the Penta J). I have recorded examples of all for sale on eBay (many of them still boxed so easy to identify for Pentamatic). Also usually listed is an oscilloscope adapter which, not surprisingly, I am yet to see outside of Yashica documentation and in a Pentamatic S system brochure, a spotting scope adapter which I have also not seen. Surprisingly, the only reference to flash as a Yashica accessory is also in the Pentamatic S brochure; “A variety of standard and special Yashica flash units, bulb and electronic, are available ...”. Below is a Pentamatic S complete with original neck strap and accessory exposure meter and 54 mm slip-on lens hood:

(Image courtesy of Chris Whelan)

This example is fitted with the 5.8 cm f/1.7 standard lens from the Pentamatic II .

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M42 Mount Mystery

One other not so well known mystery is that why Yashica, having decided to embrace the M42 mount and refer to it as the “Praktica” mount, it then chose to deploy it using the aberrant Edixa implementation of rotating the mount clockwise by some degrees. Note, the rotation is not related to the lens register as claimed by some, that remains the same. Edixa's reasons are presumed to relate to the external diaphragm coupling on some of its lenses. Yashica didn't use external coupling and seems to have had no reason whatsoever. This was brought to my attention by correspondent John Farrell who noted that “the lens from a Yashica Reflex 35, fitted to a Pentax SV, has the focusing index mark at 11 o'clock - and a Pentax lens on the Yashica, has the mark at 1 o'clock.” There are posts about this on the net and I have also confirmed this behaviour but with a Takumar on a later TL Electro-X, the rotation was closer to 2 o'clock. Manual lenses are unaffected, apart from the normally centered scales being oddly offset, but with automatic and pre-set lenses, the issue is about the ability of the striker bar just inside the camera lens mount at the bottom to hit the stop-down pin when Edixa mount and non-Edixa mount cameras and lens are mixed and matched. Usually, it is not a problem but nevertheless, it is a decision that defies explanation.

Note, Yashica M42 bodies designed for semi-automatic lenses, i.e. Penta J, Reflex 35 and J3, use the striker bar to simply trigger the manually cocked lens aperture diaphragm whereas bodies designed for fully automatic lenses use the bar to push down the stop-down pin, hold it down and then release it after the shutter closes. On the earlier bodies, the bar is directly connected to the shutter button and even if the shutter is not cocked, the button can trigger the diaphragm to fire and close the aperture down. On later bodies, the shutter must be cocked first because the camera body does the work, the lens merely providing a spring to keep the aperture blades in a naturally open position. The two systems look similar but work quite differently. Using later fully automatic lenses on the earlier bodies means that the aperture will not close down. That is especially problematic for Yashica lenses which don't have a Manual/Auto switch, unlike Asahi Optical Co. Takumars, for example.

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Claims of Zunow Sourced 35 mm Lenses

There are persistent rumours on Japanese blog sites that some 4.5 cm f/1.8 lenses fitted to the Lynx 1000 rangefinder camera released in mid-1960 were made by Zunow. We have already seen the close link with Zunow regarding the cine lenses. Chris Whelan and I have have done some investigation and Chris has even acquired two of the Lynx cameras. We don't know whether there is any truth to the claims but this is what we do know. Early lenses starting with “3” for the serial number (mostly 6 digit but one with 7 digits) until about November 1960 (we know that from the camera serial numbers) have a different style and font for the text on the front of the lens to nearly all other Yashica lenses, both earlier and later. Incidentally, the presence of “No.”, abbreviation for “number”, in front of the body serial numbers on cameras made prior to late November 1960 and “L” on subsequent cameras is pure coincidence related to new serial numbering for all models and the pattern can also be found for the same vintage Yashica YK ( prefix “K”) and Yashica 35 (prefix “F”) examples, but generally, the cameras with the early type lenses are the 1960 examples with “No.” in front of their serial numbers. (Note, whilst the Lynx 1000, Yashica YK and Yashica 35 got their identification letters in November 1960, the TLRs didn't get them until 1 January 1961, but they did instead get interim 2 digit model identifiers as early as September 1960 for some models.)

On the early Lynx lenses, “Number” is abbreviated as “No” (note, no period, or full stop). Also, the lower case “a” is different. Early Lynx lens front group on left, later on right (all later lens numbers are 7 digit, starting with “5” or “6”). The front element also sits deeper in the left early example and there are other physical differences inside.

(Images courtesy of Chris Whelan)

Why is that interesting? As noted, the font on the right lens is representative of most Yashica lenses (assumed to be made by Tomioka, later lenses changed to mostly capitals) whereas the font and spacing on the left earlier lens, and in particular the “No” but also the “a”s and “J”, are absolutely more typical of Zunow made lenses than not (less so with cine lenses, especially those fitted to Yashicas, but Zunow-Elmo cine lenses use the “No”). Below is an f/2.8 4.5 cm Zunow lens on the Neoca SV Super, there was also an f/1.8 4.5 cm lens on the Neoca SV Deluxe with similar style text and numbers on the front. Note both the “No” and the “a”s and the font generally for “Japan” (in the interests of full disclosure, the style of Zunow “a” is also used on the later Penta J and J-3 Auto Yashinon standard lenses - there is no suggestion that they were made by anyone other than Tomioka):

(Detail from larger web image)

There are only two other Yashica lenses featuring this style (with both, the “No” and different “a”). The first is a big surprise when I say it is the lens fitted to the Yashica YL. Actually, it probably isn't another lens, it is more likely the same one. The wikis and other sources will say that the YL was available with either an f/2.8 lens or an f/1.9 lens and these are widely believed to be the same as fitted to the original Yashica 35. Yes, but this camera is also found with two f1.8 lenses, one with text like the left lens of the pair above, the other with text like the right lens. Of 34 cameras I have found, 11 have the f/2.8 lens, only 7 have the f/1.9, 11 have a similar lens to the left example above and 5 have a lens like the right one. More at Yashica YL.

The second is the short lived f/1.7 5.8 cm lens released with the Pentamatic II in about September 1960 with the last example of the camera being made in January 1961 (last that I have found). Note, the font for “Japan” is different to the above lenses, more refined and closer to the “standard” Yashica style but still with the other variations noted. This lens, differed from the Pentamatic and Pentamatic S f/1.8 5.5 cm version by featuring a stop-down depth of field (DoF) preview button, 10 bladed aperture diaphragm versus 6 (9 on some early versions) and with the aperture ring spinning in the Zunow-like opposite direction (to the right to open the aperture when holding the camera). That's a big thing - until now, on all Yashica's 35 mm lenses, from the Yashica 35, the YE and YF to the Pentamatic and all their accessory lenses to date, both distance and aperture scales spin to the left for longer distances and wider apertures respectively. Pentamatic II f/1.7 lens on left, Pentamatic S f/1.8 lens (same as the Pentamatic type) on right:

The DoF preview button is interesting. Once pressed, it stays stopped down, even after releasing the shutter. To re-open the aperture diaphragm to its normally fully open position requires operation of a sliding switch next to the button. This two stage operation also featured on at least the standard lens for the Zunow SLR.

Another thing about most “Yashica” 35 mm lenses is that they tend to have longer serial numbers, 7 or 8 digits, often starting with a descriptor number that usually gives a clue to focal length, occasionally a clue to aperture and with some early lenses, perhaps some date information, e.g. Pentamatic f/1.8 5.5 cm lenses begin with 5910, 5912 and 605 which may be related to 1959 and 1960 and perhaps even months in some way (October 1959 could be finalisation of the lens design, lenses starting with 605 reverted to 6 blade aperture diaphragms and first appeared fitted to May 1960 produced Pentamatics). The descriptor number is followed by a cumulative sequence number which counts up from zero and is continuous without breaks. The f/1.8 5.5 cm lens serial numbers suggest a total of just over 20,000 made which is about the same as the total of Pentamatic and Pentamatic S cameras.

Zunow numbers tend to be shorter and all the digits appear to be part of a sequence number which counts up from some arbitrary point but it is more complicated than that. The f/1.7 5.8 cm lens serial numbers range from 424xxx to 595xxx but with quite a big gap in the middle - my database contains number ranges 42xxxx to 43xxxx and 55xxxx to 59xxxx and gaps elsewhere. The total number of lenses produced was perhaps less than 6,000, see Serial Numbers & Production below, considerably less than any interpretation of the serial numbers suggest. Both the early Lynx lens and the f/1.7 5.8 cm lens seem more Zunow-like than Yashica-like in numbering style.

Is it merely coincidence that both lenses disappeared at about the time of Zunow's bankruptcy? In all honesty, I can't answer that but it is worth thinking about. Even if Yashica acquired the remains of Zunow, there would have been a bankruptcy process and creditors wanting some return on their outstanding debt, therefore access to Zunow's plant and other resources could have been delayed for a lengthy period necessitating a change in Yashica's production plans.

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A Mamiya Twist

Just to confuse the matter more, if the f/1.7 5.8 cm lens was killed off, it seems to have been resurrected as the standard lens for the unrelated Mamiya Prismat WP, also rebadged as an Argus (on which the lens seems to be more commonly found), reputedly released in July 1962 (first identified by sharp-eyed contributor, Chris Whelan):

(Right photos, detail from lager web images)

Same Pentamatic II in left photos, Mamiya-Sekor top right and different Argus-Sekor examples middle and bottom right. Note, some sources claim that the Argus mount is different to the Mamiya but I believe that is incorrect. The people that make the claim seem to be unaware of the Prismat WP. For the first production Prismat (according to Japanese Wikipedia, the little-known Prismat CLP, an export only model released in January 1960) and the Prismat NP, Mamiya used the German Exakta mount. There was a move apparently by at least some Japanese companies to use a standard bayonet - that fell through but Mamiya used it on the WP (Sugiyama calls it “special mount”) and I also believe on the rebadged Argus variant (there are some suggestions that it was also the bayonet mount used by Asahi Optical Co., Ltd. on the 1960 Pentax Spot-Matic and Metalica prototypes). Like Yashica, the following Mamiya models adopted the M42 screw mount. Apart from being bayonets, as far as I can tell, the Yashica and Mamiya WP mounts are quite different, e.g. the film plane to lens mount flange distance of the Pentamatic is 43 mm and the Argus (also I assume the Prismat WP) is 44.45 mm.

The only obvious differences between the left and right lenses above are the bayonet mount, the colour of the scales (the scales, their placement and fonts themselves appear identical) and the Pentamatic II lens has a button on top as well as a sliding switch on the side whereas the Prismat WP and Argus lenses don't have the button but have the same switch in the same place as on the Pentamatic lens (the knob has a less pointy profile on the Sekors and on those, in the photos is sitting at the opposite end of the slot to the Yashica lens). On the Pentamatic II lens, the button stops the lens down for DoF preview and the sliding switch re-opens the aperture diaphragm fully whereas the Prismat switch combines the functions in a more commonplace implementation. All the lenses have 52 mm filter threads, 10 bladed aperture diaphragms and an aperture ring that spins the same way (there was an earlier Exakta mount Mamiya Sekor f/1.7 58 mm with 9 bladed aperture diaphragm, an aperture ring that spun in the opposite direction and an external shutter coupling - the appearance of this was quite different). Yashica advertising tells us that its lens is comprised of a fairly standard 6 elements in 4 groups, Japanese Wikipedia confirms the same for the Mamiya-Sekor.

A Japanese blogger has also made the same discovery as Chris Whelan (scroll about halfway down the page). The information is not helpful and it is only a guess that Mamiya may have been responsible for both lenses, however, there are quite a few side by side images of the two lenses (he owns both and their matching cameras).

Whose design it is and who made it are complete unknowns but if it was a Zunow design, it is possible that the original tooling etc was re-used, perhaps by Tomioka via Yashica, or even by Mamiya via Yashica. Note that there is no hard evidence that it is not an original Tomioka design, just circumstantial differences. Although possible, it is unlikely to be a Mamiya sourced design as it appeared on the Yashica first and follows the signature Yashica Pentamatic lens style. The subsequent Mamiya Sekor M42 f/1.7 58 mm looks completely different but the 10 bladed aperture diaphragm and aperture ring direction are retained so the two generations may be related. As far as I am aware, the combination of f/1.7 aperture and 58 mm focal length is also limited to the Pentamatic II lens and the three different mount Mamiya lenses.

The Argus user manual has details of f/2.8 35 mm and 135 mm Argus-Sekor lenses with fully automatic aperture diaphragms. I can't tell much from the low resolution images but they appear to share physical characteristics with the standard f/1.7 58 mm lens. Japanese Wikipedia also mentions companion Mamiya-Sekor versions for the Prismat WP. So the intriguing question is whether they are newly Mamiya designed and made or share the same source as the standard lens. They could have been designed for the Pentamatic without ever going into production. With only the standard lens and the one wide angle and one telephoto, it is hardly surprising that the Prismat WP and Argus are at least as rare as the Pentamatic.

Note, prior to the Prismat WP and Argus, Mamiya released the Prismat NP, still with the original Exakta mount and external shutter coupling but with the standard f/1.9 50 mm lens made by Canon complete with Canon markings. There is some debate about whether or not Mamiya made its own 35 mm lenses but clearly, it didn't make all of them.

Whilst much of this is guess work, the existence of the nearly identical lenses used by two different camera makers and possible Zunow connection are part of the greater Pentamatic mystery.

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Serial Numbers & Production

The camera serial numbers (see Serial Numbers Page for the different formats) for the early SLRs feature a date code followed by a sequence number which counts up production from basically zero (the first numbers are likely taken up by pre-production examples that follow prototypes). This sequence number is the last 5 digits for most early models and the last 4 for the Pentamatic S. Therefore, the highest serial numbers found give us production up to that point. There are always likely to be higher numbers still not found so it is a good indicator but not an absolute. The table below lists the highest sequence numbers for the Pentamatics and early M42 models giving a fairly accurate picture of production:

Model Production
Pentamatic
16,766
Pentamatic II
5,293
Pentamatic S
3,167
Penta J
40,757
Reflex 35
10,943
J-3
37,681

(Note, the sample size of both the Reflex 35 and J-3 is relatively low and therefore these numbers could be significantly under-stated)

The Penta J and Reflex 35 are basically the same camera and should be considered together. Whereas the Pentamatic numbers must have disappointed Yashica, the attempted updates fared much worse. Even the M42 models must have been a disappointment remembering that Yashica's sharp pricing relied on volume for profit.

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Pentamatic & Related Links

There is not much information available on the Pentamatics, or indeed the early M42 models. The best collection of information, including photos, brochures and ads is on my friend and contributor Chris Whelan's blog site, Yashica Pentamatic Fanatic at https://yashicasailorboy.com/. Look at the sidebar in “Categories”, or just enjoy the read. Chris and I have our differences of opinion but we are on the same wavelength and his discourse is lively, entertaining and intelligent.

There was a reasonably complete collection of Yashica SLRs at www.captainchaoz.talktalk.net together with other 35 mm and related models and Yashica items. Unfortunately, the hosting site was shut down in August 2018. I don't know whether the content will reappear elsewhere.

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