Although I’ve shot with quite a few auto focus film cameras, I haven’t any hands-on experience of the early, historically significant, models from the 70’s and 80’s described in this post. I only dimly recall the point and shoots I used for family photographs in the ’80s and 90s, and the auto focus film cameras I have used since I got serious about photography all date from the 1990s or later. The earliest model is the excellent Contax T2 of 1991.
I’ve sampled an autofocus rangefinder (Contax G2, 1996), a trio of point and shoots (Contax T2, 1991, Nikon 28ti, Fujifilm DL Supermini, both 1994), a 35mm mid range SLR (Nikon F100, 1999), and a top of the range SLR (Nikon F6, 2004). In medium format, I’ve used the Pentax 645 nII (2001) extensively.
The shooting experiences and results have all been good except for the Contax G2, the autofocus of which was possibly faulty.
This isn’t the story of those later AF models – though the Contax T2 makes an appearance at the end. Instead, this is a brief account of the pioneering autofocus efforts of the 1970s and 1980s. The article started as a paragraph in a review of the Nikon FE2 and developed a life of its own.
As I did my research, it became clear that this is also the story of the transition from SLR to compact cameras in consumer market and the rise of Canon as a dominant player in the photographic industry. It’s also clear I should get a Nikon L35F – it sounds excellent!
If you’re not familiar with the different types of AF systems, it’s worth reviewing the short description that follows.
Types of Auto Focus Systems
Active Auto Focus
Active auto focus systems measures the distance to the subject using waves of infrared light or ultrasonic sound and then adjusts the optical system for correct focus. This kind of AF can be used in poorly-lit environments, but only works on relatively close, stationary subjects. The familiar ‘AF Assist’ button found on many cameras uses an active AF system.
Passive Auto Focus
As the name implies passive auto focus systems use the same incoming light as the optical system and don’t beam sound or light waves on to the subject. Instead they make use of Contrast Assessment, Phase Detection or both.
TTL Auto Focus
TTL auto focus (Though The Lens) means that the system is integrated behind the photo-taking lens.
Contrast Detection
Contrast Detection (or Assessment) evaluates what the camera ‘sees’ and then moves the lens a fraction and then re-evaluates to determine whether there is more or less contrast. If contrast has increased, the system continues to move the lens in the same direction until contrast is maximised. If contrast decreased, it moves the lens in the other direction. This is repeated until contrast is at the highest level attainable.
Phase Detection
Phase Detection (PD) works on similar principles to a range finder by dividing the incoming light into pairs of images and comparing them. Mirrors and lenses, or a prism (beam splitter) are used to split the rays coming from opposite edges of the lens and a secondary lens system refocuses the rays onto the film plane.
When a point is in focus, the light rays coming from it will equally illuminate opposite sides of the lens and it is ‘in phase’. If the lens is focused in front of or behind the point in question, the light rays at the edge of the lens arrive in a different position ‘out of phase’.
The distance between the two images is then measured to see how far front-focused or back-focused the subject is. The camera then uses this information to instruct the lens which way to turn its focus and by how much. Phase detection AF is incredibly fast compared to contrast detection, and is well suited to moving subjects.
The Genesis of Auto Focus
The first auto focus patent for a ‘self focusing camera’ was filed in the United States back in 1931, by the prolific, yet largely unknown, Armenian-American inventor and entrepreneur LG Simjian (1905 –1997). Simjian held over 200 patents, mostly in optics and electronics and conducted pioneering development on the flight simulator, ATM and teleprompter.
As a medical photographer he became interested in portrait photography which led to him to invent a self-photographing camera, the PhotoReflex. This, in turn, led him to his work on auto focus.
Patents were also filed in the 1940s and 1950s and both Canon and Nikon made reference to prototypes in the 1960s and 1970s, but the first camera equipped with AF to break cover came from Leitz (Leica) at the 1976 Photokina event in Cologne, and the company is usually credited with its invention.
1976 – Leica’s SL-2 Prototype
Leitz started patenting auto focus technology in 1960 and continued to develop their system over the next decade and a half. As Leica’s cameras became more sophisticated, their engineers recognised their light meter’s sensitivity to contrast. This developed into contrast detection: two LEDs on top of the viewfinder detected the highest contrast of a subject and a motor turned the focusing ring. The prototype was based on the Leica SL-2 and was named Correfot. An observer familiar with the prototype commented:
“It worked surprisingly well in low light. It wasn’t that fast because it took a number of gears for the motor to generate enough torque to turn the focusing ring, but at the time it didn’t bother me. We hadn’t seen anything like it. The motor housing was converted to hold six batteries that lasted only an hour. It was not something they could really market.”
Leitz, a conservative company, decided not to commercialise the system and sold it to Minolta.
1977 – Konica C35 AF
Konica’s point and shoot compact C35AF of 1977 was the first commercially viable auto focus camera. This used Honeywell’s Visitronic AF (VAF) system, a patented mechanical autofocus system that used light-sensitive detectors comparing the two images in its rangefinder.
The C35AF was an autofocus version of the Konica’s C35 automatic camera with a Hexanon 38 mm f/2.8 lens, a leaf shutter, built-in flash, and automatic exposure.
1978 – Polaroid SX-70
The first AF Single Lens Reflex (SLR) camera arrived in 1978 in the form of the Polaroid SX-70 Sonar OneStep instant camera, which was equipped with an active sonar autofocus system. This is essentially the original Polaroid Land Camera, a true (folding) SLR, with a sonar autofocus bar grafted onto the body.
1979 – Canon AF35M
The Honeywell Visitronic used in the Konica C35 AF was the system of choice of most manufacturers offering AF until Canon’s CAF system arrived in 1979. This system quickly became the standard for autofocus cameras. The CAF equipped Canon AF35M of the same year (the first of the Sure Shot range) offered auto focus, auto exposure, auto wind on and auto rewind. Canon claimed it as the world’s first 35mm autofocus camera.
The stage was set for a contest for auto focus supremacy and the compact cameras, and Canon, had a head start.
1981 – Pentax ME-F and Chinon CE-5
Auto focus 35 mm Single Lens Reflex cameras (SLRs) arrived in 1981 with the Pentax ME-F, which was based on the Pentax ME Super of 1979. This required the autofocus SMC Pentax AF 35–70 mm zoom lens equipped with a drive motor. It is easily recognisable by the bulky battery compartment below the lens. The ME-F used through-the-lens (TTL) electronic contrast detection system but focused poorly and did not sell well.
In the same year Chinon produced the CE-5, a Pentax K mount SLR that used infrared with large heavy lenses with lens-mounted motors. In the words of the manufacturer:
“Chinon “direct focus” electronics incorporated in the CE-5 match precisely to similar electronics in the optional 35 – 70mm zoom auto focus lens. Just depress the CE-5 shutter button to activate the 35 – 70mm AF lens; instantaneously the lens barrel rotates to the precise focus! This ingenious system even prevents accidental shutter release before the lens has completed focusing”.
1983 – Olympus OM-30 and Nikon F3AF
In 1983 Olympus introduced the OM-30 (OM-F in some markets), an updated version of the OM-G/OM-20), that could be used with an auto focus 35-70 mm lens which had a motorised focusing ring.
The camera offered three focus modes. With electronic autofocus mode, touching the release button focuses the lens ‘instantly’ (‘one touch autofocus’) with an electronic beep for focus confirmation. In electronic focus-aid mode, focus is obtained by rotating the lens focusing ring while watching LEDs. A tone sounds when the camera has obtained focus. Lastly there is ‘optical mode’, which is manual focus via a microprism/split image rangefinder and matte area.
Unfortunately, the auto focus mode was often inaccurate, slow and dependent on one zoom lens. As it offered focus confirmation with other lenses Olympus also promoted it as ‘the first focus-confirmation SLR for a photographer as serious as you’.
Nikon introduced auto focus with the F3AF which was based on the F3, and utilised TTL contrast detection. The launch was accompanied by two new auto focus lenses with internal focus motors, an 80 mm f2.8 and a 200 mm f3.5. These lenses featured Nikon’s usual optical excellence but their AF performance was relatively poor and the offering wasn’t successful.
Nikon also introduced its first compact AF 35mm camera, the L35AF, which was well received due to its excellent f2.8 35mm lens and accurate AF. The same factors make it popular with film photographers today for whom it has some bonus features. There’s a 46mm filter thread, and through the lens metering; there are icons in the viewfinder that will tell you where it is focusing as you shoot, and it also has a manual setting for ISO to over-ride DX if you want to push or pull the film.
1984 – Compact Auto Focus on the Rise
Nikon was the last of the major SLR manufacturers to offer compact AF cameras with the L35AF. By the end of 1984, that model had outsold all of Nikon’s SLR bodies (F3, FA, FE2, FM2, FG, FG-20, and EM) combined in that same time period.
At the same point in time Japanese 35mm SLRs had only 33% of the worldwide market versus 67% for 35mm compact cameras. In 1977 market share was 57% in favour of SLRs.
During the 70’s and ’80s there had been a shift from metal bodied, manually operated mechanical SLRs to more compact, automatic plastic-bodied models. This was supported by the rapid advances in electronics, including the rise of the integrated circuit, which made both automation and miniaturisation easier. The SLR manufacturers targeted amateur photographers using rangefinders and thought they would upgrade to SLRs equipped with sufficient automation. As the market share figures above show, they were not successful and compact cameras became the norm for amateur photographers.
1985 – Minolta 7000 and Canon T80
The Minolta 7000, released in 1985, was the first SLR with an integrated autofocus system – both the AF sensors and the motor were housed in the camera body. It was the first AF SLR that could focus quickly, accurately, and operate in low light levels and made use of phase detection (PD) autofocus. Minolta also provided a wide selection of lenses and accessories and priced their new Alpha (A) mount camera at a relatively affordable price point for mid-level enthusiasts. It sold well.
Canon introduced the Canon T80 as its first autofocus 35mm single-lens reflex camera that same year. It looked like nothing that came before, or after it, for that matter. The T80 had a modified FD mount with signal transmission capability known as AC, and a linear CCD array for TTL image contrast detection. There were three AC auto focus lenses available: an f1.8 50mm prime and two zooms – 35-70mm and 75-200mm.
Learnings from the Canon T80
The T80 was discontinued just over a year after its launch. The effort wasn’t wasted though as Canon explained on the 30th anniversary of EOS:
“The idea of a fully-electronic mount is largely attributable to the experience we gained from developing the T80, an AF camera that used lenses with built-in motors. In the case of telephoto lenses, having the motor inside the camera made it difficult to achieve high-speed focusing. Coordinating the aperture drive was also a test of limits due to the complex mechanisms of both the camera and the lens. However, we persevered because we felt that the future of next-generation cameras hinged on the development of a new, fully-electronic mount.”
In March 31 of that year Canon leaders and engineers from around the world met to discuss the development of a new system, known at the time as the “Entirely Organic System.”
1986 – Nikon F-501
Japanese industry analysts were predicting that the shipment of AF SLR cameras in Japan in 1986 would outstrip manual focus models. Nikon responded by hurrying to implement the ‘body-powered’ AF Nikon F-501 in April 1986 with TTL passive phase-detection autofocus and in the same year introduced new autofocus (AF) lenses.
The polycarbonate-bodied F-501 was the first successful auto focus SLR and offered automatic film loading and advance as well as a built-in motor drive. This provided single or continuous modes and a maximum film advance speed of 2.5 frames per second (frame/s) in continuous mode. Nikon adopted some design concepts from the camera in the Nikon F4.
The new lenses relied on the autofocus motor in the camera body to drive the focus mechanism via a screwdriver on the lens mount and could communicate electronically with compatible AF cameras.
1987 – The All New Canon EOS System
Canon introduced its ‘built from scratch’ AF system, which used a new lens mount for lenses with its own AF motors – the EF. Breaking compatibility with Canon’s FD mount, the aperture and focus were controlled via electrical contacts, with motors in the lens itself. In Canon’s own words from the same 30th EOS anniversary interview with the leading engineers:
“Before the EOS series was launched, our cameras featured the FD lens mount. However, a fully-electronic mount was essential in order to achieve a high level of AF technology with our wide variety of interchangeable lenses. To realise a high-precision AF that moves the focusing lens elements optimally according to the focusing distance or zoom position, it was a must for the lens to exchange information with the camera as well as to eliminate any mechanical error. This is why we chose to control the camera system by linking the camera with the lens via electrical communication. Through this, we were able to achieve high-speed and high-precision AF even at such super telephoto focal lengths as 600mm. What’s more the aperture was also electrically linked to enable smooth video shooting and playback, a feature that is taken for granted on cameras today.“
The system was introduced with the Canon EOS 650 in March and within two months it was the best-selling SLR in Japan and Europe.
1988 – The Nikon F4 and the Second Generation of AF
The Nikon F4 was introduced in 1988 as the next generation in Nikon’s line of F series professional cameras and was the first professional Nikon to feature a practical autofocus system. The F4 offered outstanding backward compatibility as it could mount any of Nikon’s manual focus or AF lenses from 1959 onwards.
The second generation of AF SLRs also began to appear in that year, the Minolta 7000i and Nikon F-801 being the most notable.
1989 – Compact Auto Focus Dominates
Of the 818,000 SLR produced in Japan in 1989 Over 90% were AF models. The manual focus SLR era that had been dominated by Nikon was over. Canon was the SLR market leader and Minolta was in second place. However, Minolta’s lead over Nikon was only temporary and the company was soon overhauled.
It wasn’t just manual focus SLRs that were declining. According to worldwide market share (CIPA figures) Japanese 35mm SLRs had only 15% of the market versus 35mm compact’s 85% in 1989. SLR dominance was effectively ended by auto focus compacts.
Post Script – Honeywell Vs Minolta
The design of phase detection autofocus came from Honeywell and their patents of the 1970s. Honeywell sued Minolta for patent infringement and won, so all the camera manufacturers had to pay Honeywell for the rights to use phase detection autofocus.
A 1991 court decision found Minolta guilty and Minolta paid Honeywell $127.5 million in back royalties, and for license rights to continue using autofocus technology. The world’s camera manufacturers paid Honeywell over $300 million for licenses to their autofocus patents.
The Contax T2
The earliest auto cameras arrived in the 1970s and 1980s, but as we are wrapping up the story in the early ’90s it seems reasonable to give the Contax T2 of 1991, my earliest AF camera, a mention.
The T2 was one of a range of high-end compact cameras produced by Contax between 1984 and 2002. The manual focus T was introduced equipped with a Carl Zeiss Sonnar T* 38 mm lens. The T2, used the same lens in an active autofocus system.
The T2 offered a high degree of automation, including auto focus and Program AE, coupled with a decent level of user control, including Aperture Priority exposure, manual focus and exposure compensation. Constructed of titanium and with a renowned lens, the T2 was a luxury model that has since become sought after and expensive.
It is rather too bulky to fit in any but the most capacious of pockets but it is very portable nonetheless. Its ideal for when you want a film camera with you and space and weight are at a premium. Those events where ‘professional cameras’ (those with removable lenses) are prohibited are also ideal for the T2.
The only real drawback to the T2, other than its cost, is that Program AE mode and Aperture Priority f2.8 share the same setting, so you can’t shoot wide-open unless the exposure level permits it.
Into the Digital Era
In the SLR market lens-mounted motors became the norm for auto focus, and in 1998, Nikon introduced AF-S lenses with their own ultrasonic “silent wave” motors built in, only a year before the launch of the digital Nikon D-1.
Nikon had the benefit of backward compatibility, but Canon had over a decade of experience with EOS by then and had gained a significant advantage. The two titans would continue to slug it out in a contest that was soon to enter the digital era, but they would be joined by electronics behemoth Sony, which acquired Minolta and its auto focus technology….