Early History of Single Lens Reflex (SLR) camera
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update 18. March 2007

  Picture of Pentax Switzerland

1954 Asahiflex-IIB
Asahi Optical Company launched the first SLR with Instant Return Mirror. Just imagine: Before this camera, when pressing the trigger of an SLR, the finder became (and kept) black! So arguments can be made that this camera was the first usable SLR  - beforehand it only was a niche market for EXAKTA in Dresden and other firms like Pentacon mostly in the East part of Germany (GDR) - but not accepted by ambitious 35mm photographs who preferred Rangefinder (RF) cameras from LEICA, CONTAX and their Japanese copyists in the early 1950's...
Whereas Nikon, Canon, Minolta and Fuji started Camera business with RF-Cameras before - after the success of PENTAX - they turned to SLR design, PENTAX really started with SLR (first camera: Asahiflex I of 1952) and never produced a RF design.
The lens above is a Heliar-Typ (5 elements/ 3 groups) - a rare design for 35mm cameras...usually in the f/2.8-range are Tessar-types with 4 elements. Pentax continued with the Heliar type to recent years..

The Heliar of  Voigtlander - prewar design - continued as Pentax SMC MACRO 4/100mm well into the 70's	Identical schema (5 elements/ 3 groups f/2.4 58mm for Asahiflex-IIB

What kind if cameras are that ?
After World-War-II these Single Lens Reflex cameras- SLR - were smiled by estabilshed photographs because they are quite ugly, odd, heavy and slowly.compared to fast LEICA or CONTAX with their elegant rangefinders. Phtographyic industry speaks German and most, if not all SLRs come from the communistic part of Germany, GDR. Well, what qualirty is to expect from commustic countries? And Japan? No own ideas, just copyists... no copy can be better than the origin... this talk from toffee-nosed experts and sales people went again and again for more than twom decades... until 1970 the West German camera idustry was went to hell in a handbasket.
At 1950 the critics about the SLR are not alsolutely wrong... Look ar these diminutive focussing screen - hip-shooting you need excellent eyes to focus these small screens - even with a Rolleiflex 6x6 this isn't so easy and it has 4x its film format.. either it is too bright or too dark and you see nothing.
SLR's are better with long focus length lenses - maybe true, but, dear, who in the world has lenses with more than 135mm ? Just a handfull of photographs. Press Photgraphs,i.p. Americans, take these 35mm cameras as toys - in a crowd you need a big camera for getting respect and room to work. So they take these bulky Graflexes.  This will change in the late 1960's after war stories from photgraphs in Vietnam taking a rescued from a bullet by their NIKON camera... this happend not too often... In the 70's and 80's professional cameras are equal to SLR in peoples's believe. Rangefinder sales went near to zero because no one thinks you can make usefull photos with any other stuff than SLR - industry makes cameras who only looks like it... A few landscape and promotional photographs keep the 6x6 or Large Format solely. Even todays digital professional tools form CANON or NKON are looking like Film-SLRs even there is no need for that look any longer.. this is a great success story!


 1936 - Ihagee = invention of 35mm SLR
1936 - Leni Riefenstahl is filming Olympia in Berlin for Adolf Hitler, wherefor ZEISS develops a high speed f/2.8 180mm Sonnar-lens. Not far away from the capital, in Dresden  the company Ihagee brings the worlds first SLR camera for für 35mm cinema film to the market, the Kine-Exakta. A modern camera with horizontal focal plane shutter from 12 to 1/1000s. 1940 the company of the Dutch owner is breakuped, civil production is cancelled - camera production is war-important! Another Ihagee invention: The fast film advance lever!
Prior to this,  Ihagee also made the first SLR (Exakta-A) for small roll film (127-format which was 6,5x4cm) in 1933.

 1937 - GOMZ Sport
It was said that Russian GOMZ Sport was the first 35mm  film SLR prototype (1935) but it takes them as late as 1937 to bring  it to market and lacks the impression and a good lens series.


1939 - Praktiflex (first return-mirror SLR)
You think the Asahiflex IIB was the first SLR with a mirror that returns after firing? Wrong. Camera factory Dreden-Niedersedlitz (after the war VEB Pentacon) build them 15 years before Asahi Optical Co, making nearly 60.000 of them, from 1941 on with a 1/1000s. The last big run, a simpler version missing the return-mirror (1946-1948) is for Russian war reparations. Like the Exakta, a somewhat bulky camera. lens adaption with M40 screw mount, abnd probably at last M42. There was no interlock between the whole mirror way upwards and downwards - just a connection when pressing the trigger the mirror was lifted, so it was called comeback-mirror instead of instant-return-mirror. Unfortunatly, their successors Praktika and Praktika-FX lacks this feature, nor enhance it like Asahi-Optical did, and so it was quite oblivious...


1949 - Contax S
Around 1940 at Zeiss-Ikon nearby in Dresden, maker of the famous CONTAX Rangefinder cameras, which together with their lenses many  photographs oft the time take for better than the prewar-LEICA, the attitude is more innovative than it is at the competition in Wetzlar. A CONTAX-SLR is developed, to be called SYNTAX. The war stopped everything. After the firestorm Zeiss-Ikon is in debris. The company is diveded as the whole nation. Zeiss-Ikon Dresden is restructered as public owned enterprise (VEB, Volkseigener Betrieb) and after backup to procution, the idea is resumed. Result is the Contax S, with the Rectaflex first SLR with a viewer prism. The world isn't side-inverted for the SLR-photograph any longer...
The first camera with M42 screw mount together with the Praktika
Build in numbers of 26.000, the Contax S isn't as successfull as they merrit to.


1950 - Ihagee Exakta Varex
Ihagee, now VEB as well, match up: The camera is available with prism or chute finder - first changable finder system at an SLR !

1952 - First Asahiflex
Different from NIKON, CANON, YASHICA and other Japanses companies who started with Rangefinder cameras, building LEICA or CONTAX prewar camera copies, Asahi Optical is convinced to SLR right from the beginning.
Except from compact size which reminds to a screwmount-LEICA there is nothing special with the first "Pentax". Not a prism yet. shutter speed to 1/500s only.

  1954 - Press Aperture at lens
One disadvantage for fast shooting compared to RF cameras, you need to focus at full aperture and after this stop-down for shooting. For the leafshutter-SLR ZEISS-IKON Contarex (no changable lenses) the fist automatic diaphragm is shown 1953. Poor Contarex will never be equipped with an instant-return-mirror until ceaing production in 1970. For changable lenses and with focal plane shutter, one year later Exakta solves showa attachments for lenses upstream to the trigger which stopdown immediately when pressed. At this camera all controls are side-inverted to "Leica-standard": A good choice for lefthanders. But this attachments are not common for every lens, makes trigger slow and lens-mount more complicated. Not fully satisfying...

1955 - Miranda T (Orion T)
The first Japanese Pentaprism SLR - changable like Exakta Varex, but more compact and sleek lined design. Missing: lever advance, instant return mirror....


1956 - Pentacon F/ Contax F
This is the first camera with innert aperture triggering - transmission within the lens mount lens mount - first "real" autmatic diaphragm - the right approach!
Successor of the Contax S, but missing the instant return mirror and fast lever film advance - invented 15 years earlier in the same city this camera was produced.. don't change too much stuff ! This is the last innovation of GDR made cameras for 13 years..!

1957 - The original Asahi-Pentax
Not a revolution technically, the "original" Asahi Pentax (later called AP by collectors) this camera at first combines these new features in one and therefore, is the best buy at their time:

• Pentaprism
• Instant return mirror
• Film fast lever advance and rewind crank
• M42 screw mount (lenses named "Takumar")

All this combined with a adorable clear, modern design which sets standards for this genre for 30 years! In addition, it is compact and lightweight - just 580g compared to the usual 800-900g Not cheaply made - you can feel it. Half a century later, they are working as good (or sometimes, as bad) as the German competitors of the same vintage...
PENTAX isn't too proud to mit their logo for trading marks like Tower, Heiland, Honeywell etc. to gain sales share in USA or other markets. They yield sales effort to those who know the market better than they do in the late 50's, early 60's. Later than, if ciustomers remember to a good product they will buy it under tehir real name.

It is also a good idea to copy the M42 screw mount of East-German Pentacon - later called Pentax scremount by many - even if it is clear to that time that any screw mount lens adapting isn't the best idea technically.
But Pentax first target is selling cameras - Carl Zeiss Jena and other East German optical companies doing some of the best lenses of the world at that time, and you can use it! Next Pentax started to develop their own lens series, and they do it different than East German optical industry: More compact, more speed, better finished, modern looking - and from optical quality (something which isn't seen outright) at least equal.

For West-German camera industy M42 is something disgusting. But lenses or cameras never fear of contact, don't konow about politics, are either good or bad designs. This lesson to learn takes ZEISS-IKON West 10 years  - picture is a M42 screwmount Icarex 35S - but then the last train is gone: too expensive, too clunky, too heavy, technically outmoded...

East-German companies don't do it better: The name "Pentax" (of Pentaprisma and Contax) is an VEB Zeiss-Ikon idea, and is sold for little money to Asahi Optical in 1954. Not the best decision of the company in terms of trademark problems and lawsuits with West-German companies like ZEISS AG Oberkochen.. at the end ZEISS-IKON in Dresden und CARL ZEISS in Jena will lose right on their ancestral names in international markets !

1958 - Pentax K
second stroke of Pentax:

• semi-automatic diaphragm mechanism through the lens mount with a pin to  the lens (called "Auto-Takumar" - buit you can use every manual lens as well)
• shutter with 1/1000s now, but stil with rotating dial and second low speed dial

LINK: More of  my early PENTAX SLR cameras...

 1958 - ZUNOW is a small, fine Japanese factoy making cameras and lenses in low numbers. Building the second Japanese SLR with Instant return mirror and automatic diaphragm called Zunow-matic Diaphragm System - and bayonet lens mount. Starting in August 8 pieces a day...


  1958 - Minolta SR-2
If you ever own a Minolta, will you recognize it as a Minolta? For sure. You would think this one is nearly 50 years old? Never...
In business as a maker of (quite well made) LEICA screwmount copies, this is Minoltas first SLR... and a great one! This design will last the next 25 years as well!
First Japanese SLR with non-rotating single speed dial (you can buy it at a LEICA M3 since four years now), third Japanese camera-maker with instant return mirror and semi-automatic diaphragm, rewind crank, fast lever advance - plus a modern bayonet lens mount, without breech lock - basically the same which Minolta still use today, so it's only 4 years younger than LEICA M which is also still in use.
The first SLR with motor-drive connector - unfortunately Minolta never decided to produce one...
First company with dual-coated lenses (called multi-coated but that was not the case)
So with all these great features, why it hadn't the same success than Pentax and Nikon? Probably because of the proprietary lens mount and small lens family. So it keeps as a typical amateur camera till present - but other than ZUNOW and MIRANDA has a luck to survive.
This was a great year for Japanses camera designers, probably the best ever. Unmortal designs like the CANON-P, NIKON SP or NIKON-F were created.. no, the copy-era was gone, forever. Japan took the lead.

1958 - Miranda
Just know Miranda as a girl from "Sex& the city" ?-
No matter, the company is gone for quite 30 years. But in the 50's they made nice modern cameras. In 1958 they had no instant return mirror yet - a real drawback - but was catched up one year later with the Miranda C (picture). Similar to Exakta Varex are Press diaphragm and changable prisms. Bajonet mount. In the early 60's the same selling success as Pentax.


1959 - NIKON F
in the same year the NIKON F took off..  which became the first professional SLR of the world for more than a decade.
See seperate page: "The NIKON"


 1959 - Zeiss-Ikon Contarex
The West-German answer to the Japanese focal plane shutter cameras is the CONTAREX - 1958 showed at Photokina - excellently finished, but hevyweight (910g without lens) and far too expensive and complicated. Even at its high price - 1030 DM in 1964 (it was doubt that even this price was cost-effective) and huge accessory program it was not  first choice for professional photographs. Ugly selenium meter (bulls-eye) coupled both to shutter speed and aperture dial (which is part of the camera, not the lens). 32.000 produced until 1966. One segment lower there was the CONTAFLEX: a leaf shutter camera with a small series of exchangable lenses (slow, due to the size requirements of shutter). More success than the Contarex - but not enough either to keep them survive...


1962 - "Pentax Meter" 
This is the Japanese solution of the problem - a simple cds-meter mechanically coupled to the speed dial sitting on the prism.. Costs a lot less, and more exact than the outdated selen-meter. This also spoils the nice line - but at least it's removable...

1964 another PENTX invention, the first camera with Through-The-Lens (TTL) light metering - today a self-evident feature for quite every camera. Moreover, PENTAX was the only maker who completely integrated the meter into the body so it wasn't visible from outside, or disturbed the look. This was the SPOTMATIC - though Spot-Metering wasn't realized in series but a more common whole-field-center-orientied metering.

Pentax Spot-Matic (Prototyp TTL-metering 1960)	Topcon Super D 1963 - world first TTL open aperture metering SLR camera

TTL-metering prototype was finsihed 1960 - shown at the Photokina in Cologne - but took additional time to come to market.
Invented theoretically 1939 by German Karl Nuechterlein, chief designer at Ihagee/Exakta for SLR, and again 1957 for Canon Rangefinder cameras, at this time there were no light-sensitive cells available small enough to place them behind a lens or into a prism, but around 1960 battery-driven CdS-cells became available for light metering purpose, at first by Pentax and Nikon.

First at the market with TTL metering by a few months was the Japanese TOPCON with Exakta bayonet mount and extravagant styling... in the 70's that sharp-edge styling became modern.. if you like it or not, with one thing TOPCON was dead-right in realization: TTL-metering only make sense as open-aperture-metering . Hell, for what reason exept fast shooting was automtic diaphragm invented eight years ago?? To realize that, the meter in the camera needs to know how many stops the lens is actually stopped-down by the photograph. For that you need a second pin in the lensmount (or, in case of the Nikon F, a coupling device outside on the aperture ring). This wasn't possible to transmit in a screwmount at that time, and that's the reason why PENTAX failed to realize open-aperture metering until 1973 with the Spotmatic-F (Full apetrure). The first company doing open-aperture-metering with a screw mount was 1969 Praktica. They solved f/-stop-transmission problem electronically - resistors within the lens - while Pentax made it mechanically with a pin moving according to f/-stop position. mechanically.


1965: Nikon Photomic FT (open aperture metering), price 436.50 USD, and Pentax Spotmatic (working aperture metering), 375 USD, both with fast f/1.4-lenses

Despite this deficiency the Spotmatic was a great selling success (2 Millions in two years) and made Pentax to a big player in business. Now they reaped the fruits of their work since a decade ago. An argument can be made that two cameras, PENTAX SPOTMATIC and NIKON F drove the German camera industry out of the market, or famish them to niche players.. But typically for Japanese companies, they don't rest on their laurels.

1971 came the first lens Multicoating (Super Multi Coating, quickly abbreviated SMC) - overdue for the optical designs becoming more an more complex in the last decade (ZEISS T* was introduced one year later but didn't make a lot of business in 35mm cameras after finally ceasing the Contarex). At the same time the first elctronic Automatic Exposure (aperture priority mode) SLR: Pentax ES - making the body a bit more clunky... AE - anyone able to shot pictures yet without this sluggard's settings?

1975 finally Pentax said godbye to the screwmount M42 that was out-dated more than a decade, and introduced a Bayonet connector - similar to IHAGEE, MIRANDA. MINOLTA, ZUNOW, NIKON, CANON and other did long before. Different to them, Pentax left the K-Bayonet patent open for other manufacturers. Today the K-Bayonet is still the best backward-compatible lensmount, preserving the usability, if not the value, of equipment. You cannot use electronic features of a KA-lens but at least you can use it manually with a manual camera. In this era my little MX is linked to..  End point and masterpiece of the mechanical epoch. Today the times when SLR were build like fine-mechanical clockworks are gone. In parallel, cheap electronic modules starts to substitute mechanical components (see Pentax ME) - of course PENTAX doesn't stick to mechanics but is present in this development in the first row. This heralds an inconceivable reduction of space and lowering of costs and prices... leading to today's digicams and isn't at its endpoint yet...

more Pentax: Early Takumar Lenses
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