Take the top off an AE-1 and you are presented with the electronics in an “A” Series camera. A flexible printed circuit is wraped across the top of the pentaprism studded with integrated circuits, resistors, capacitors and potentiometers. And there are wires, lots of wires. Crude by today’s standards but cutting edge in 1976.
The “A” Series Cameras
The Dawn of the Electronic Camera
By the 1950’s the calculating ability of electronic circuits were well understood. Amplifiers were in common use in science and industry. The ability to accurately calculate time intervals was well known. And it was all done with vacuum tubes. Unfortunately these electronic circuits were large, cumbersome and of no use to traditional photography because you could not fit them into a hand held camera.
With the invention of the transistor in 1947 these circuits began to shrink, power requirements were reduced and the heat caused by the vacuum tubes was almost totally eliminated. But the components were still too big to fit into a camera. It was not that engineers did not know how to design the circuitry for fully automatic exposure but that they did not know how to make it small enough.
On the side of the pentaprism under the wires and resistors you can see an integrated circuit soldered onto the flexible printed circuit board. Today those wires and resistors would actually be mounted on the chip itself.
In 1966 integrated circuits were becoming available with 10 to 20 transistors on a single chip but the packaging was large and awkward to mount on a circuit board. There was still a long way to go.
In 1972 a trend appeared with the introduction of the Olympus OM-1 SLR towards smaller and lighter cameras. The OM-1 was very successful. It was a manual SLR with a match needle TTL light meter system much like the Canon “F” Series cameras but smaller and lighter. Beside it the Canon cameras appeared larger, louder and dated.
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Canon realised that they had to freshen their line of cameras and they set up a design team to create a new camera. The goal was a smaller lighter camera with fully automatic features. The problem to be solved was that the automatic features Canon sought would require complex mechanical mechanisims that would scarcely fit in an SLR body, especially a smaller one, unless ….. the mechanical mechanisms could be replaced by electronics.
What could be done electrically. Well, obviously the shutter timing. And while we are at it, the self timer as well. The shutter release was mechanical. Why not use electrical selenoids? The meter range could be extended with signal amplification. And automatic exposure settings could be calculated and implemented electrically.
At this time Canon’s business machine division was working with the American firm Texas Instruments to develop electronic calculators that used integrated circuits to perform calculations. Canon had “in house” knowledge of these new devices and their capabilities.
By 1976 Canon’s engineers found that by employing electrical solutions to these problems they could eliminate somewhere around three hundred mechanical parts and still produce a smaller lighter camera with electronic shutter control and automatic aperture settings. And that camera was the AE-1, the first of the “A” Series of cameras.
All of the cameras in the Series had aluminum body frames, injection molded top decks and many internal plastic parts, all of which kept costs down. Canon went to pains to conceal the use of plastic by giving this top cover either a satin chrome or black metallic feel and finish. They were never intended as “pro” cameras, although many ended up in professional use, but rather were aimed at the newcomer market. The “A” series were the first SLR’s purchased in the millions. Extensive use of automation, simplified design and the use of less expensive parts, all made for an easy to use camera of considerable sophistication that was affordable. It was a winning combination. With this camera series, Canon was on the way to overtaking its old nemesis, Nikon.
“A” Series Cameras and their Introduction Dates
The “A” Series began in 1976 with the AE-1 and continued until 1982 with the AL-1 which was the last in the series. These were electronically operated cameras and required a battery not only for the light meter but to control the shutter as well. Without the battery they will not function at all.
| AE-1 (Chrome) | 1976 | AV-1 (Black) | 1979 | |||
| AE-1 (Black) | 1976 | AE-1 Program (Chrome) | 1981 | |||
| AT-1 (Chrome) | 1977 | AE-1 Program (Black) | 1981 | |||
| A-1 (Black) | 1978 | AL-1 QF (Chrome) | 1982 | |||
| AV-1 (Chrome) | 1979 | AL-1 QF (Black) | 1982 |
Starting with the AE-1 Canon started down the road to fully automatic cameras. But that was a slow evolution in features through many models of camera. This is as good a point as any to look at some of the terms and processes that come up when discussing this evolving technology.
TTL (Through the Lens) Metering
At first cameras had no means of measuring light. That was done by guessing and experience and then by light meters. When I started taking pictures in the 1950’s I had a light meter which I carried with me in my pocket. Then cameras came out with a light meter attached to them. And finally the light meter was built into the camera body. The Canon rangefinder Model 7 had such a light meter. So did the Canonflex RM. But those light meters could not see what the lens saw. They measured light coming from the general direction the camera was pointing. In most cases this was enough but in some it was not.
In April of 1965 Canon introduced the Pellix camera in which the light meter was actually inside the camera measuring the light that arrived through the lens. This was the the beginning of what was to become the standard across the industry: true Through the Lens (TTL) Metering.
On early cameras the shutter and/or aperture were set by the operator. When light meters were first mounted on cameras they were still not part of the work flow. They measured the light but they did not communicate with the camera. The photographer still set the shutter speed and aperture based on the light reading. Even with the first TTL light meters, the exposure was still set manually.
This is the Selector Dial on a modern 60D camera. The setting above the Green Square Symbol provide maximum control over the camera.
Aperture Priority (Av)
Aperture Priority is an exposure method employed on modern cameras. In this mode of exposure setting, the lens Aperture is set by the photographer and then the shutter speed is adjusted automatically by the camera to obtain correct exposure.
On Canon cameras this setting is indicated by “Av” (an abbreviation for Aperture Value) on the selector dial. This allows the photographer to control his depth of field himself and not leave it to the camera.
Shutter Priority (Tv)
With Shutter Priority the shutter speed is set by the photographer and the Aperture is adjusted for correct exposure. This setting is indicated by Tv (short for Time Value) on the selector dial.
This would be used, say, in sports photography where the photographer wants to ensure a high shutter speed in fast moving situations. Once set, the camera will not try to change it. It will adjust the incoming light with just the aperture setting.
Program Mode (P)
Program Mode simply means that the camera itself will set the shutter or aperture, or both. On Canon cameras this setting was indicated by the letter P (for Program). It operated in a slightly different manner on various models but it always involved the camera selecting at least one of the variables itself.
Automatic Mode (A)
On Canon cameras this is indicated by a green rectangle on the selector dial. In this mode the camera selects all the variables by itself, automatically, without intervention from the photographer. Most experienced photographers stay away from this mode of operation because they want more control over their pictures. However, for inexperienced customers who want to be able to shoot “snapshots” without having to learn a bunch of controls and theory, this mode is a blessing.
Manual Mode (M)
Manual Mode (M) is indicated by an M on the selector dial and in this mode the operator selects all of the settings himself and any programmed or automatic features are disabled.
PASM Exposure
You may come across the expression “PASM” which is simply an acronym for Program, Aperture Priority (Av on Canon), Shutter Priority (Tv on Canon), and Manual. It means that the camera offers all of these basic modes of exposure.
Not only are there different modes of auto exposure, but there are different ways in which the cameras measure the light. The lens takes in a scene but what part of that scene is actually measured? Well, that depends.
If the light is measured towards the center of the scene, with most emphasis taken from the center and less influence taken from the edge of the scene, the method is called Center Weighted Average metering. This was an early method of metering and it is the only mode found on many older cameras.
Spot metering is exactly what it says: a spot is chosen in the scene and the measurement is taken from it. This allows for very precise measurement of an area so that you can chose what in the scene is recorded in the most detail. This is favoured by people who like to exercise maximum control over the image. It is useful, for instance, in a strongly back lighted image. It allows you to set the exposure for the foreground image which may be in shadow.
Partial Metering, sometimes called Selective Area Metering, is like spot metering except the spot that the camera samples is larger. In Canon SLR’s this was usually in the order of 11 or 12% of the image area. This first became a thing in the New F-1 camera and then introduced again with the T70.
Evaluative Metering
Evaluative metering is Canon’s term. Nikon uses “matrix metering” and Pentax and Sony use “multi-segment metering” to describe the same thing. The viewfinder is divided up into zones and measurements are taken for each zone. The recommended exposure is then weighted towards the zone nearest the chosen auto focus point.
Cameras in the Collection
But, enough of the simple explainations. I know they are almost too trivial to mention but they may help someone figure it all out. I remember when I didn’t know any of this stuff.
Here are some of the A Series cameras in the Collection:
C-02
Canon AE-1
1st microprocessor SLR
April 1976 thru 1984
C-100
Canon AT-1
AE-1 without Auto Exposure
Introduced December 1976
C-14, C-15, C-17
Canon A-1
Programmed Auto Exposure
April 1978 thru 1985
Canon AL-1
Introduced March 1982
Canon AL-1 Black
Introduced March 1982
Canon AV-1
1979 thru mid-80’s
C-161
Canon AE-1 Program
Introduced 1981
C-144
Canon AV-1 Black
1979 thru mid-80’s
I am not in any way connected to or supported by Canon. I chose their camera line and have stayed with it. I cannot recall why. But a Nikon camera is fine technology and takes a wonderful picture. So too with Sony and the others. But I have been happy with Canon and so I have begun my collection here. One day I may add other brands to my range interest. But that is for another day.