Canon EF
The Canon EF was the first Canon system camera with built-in fully automatic exposure control. This was designed as an automatic shutter . The camera belonged to the F series and had a connection for lenses with FD bayonet . It appeared in November 1973 and remained in the range until the Canon A-1 was released, but with the introduction of the Canon AE-1 it was only relevant in the semi-professional sector.
classification
F series
The Canon EF appeared as the last F-series camera. New to the EF was the built-in shutter control. Such an automatic was already available in the EX and F-1 models , but the EX with its set of lenses was not a fully-fledged system camera and the F-1 required the expensive EE servo viewfinder from the accessories program and in addition either a connected, also quite large battery pack or the power supply of a connected motor drive was used as a power source.
This automatic aperture was made possible by the FD lenses released in 1971: an aperture value calculated by the camera was mechanically transferred to the interchangeable lens and closed the aperture accordingly.
distribution
Due to the technically complex automatic, but also the metal shutter, the Canon EF was quite expensive and therefore only sold in small numbers. With the normal Canon FD 50 mm f / 1.8 lens, it cost around DM 1200. Canon was only able to change this with the subsequent A series, which, thanks to advanced electronics, managed with fewer components and only had a cloth fastener.
Comparison with other brands
Konica had cameras with fully automatic exposure, beginning with the Auto-Reflex, in its range since 1965, and it was also an automatic shutter, but still mechanically controlled. Electronic control was first used in 1971 on the Asahi Pentax Spotmatic EX, followed in 1972 by Nikon EL and Minolta XM. All three cameras were time machines. The first shutter automat with electronic control was the EF in 1973. Beyond this, this camera did not bring any innovations, but it was clearly designed and easy to operate.
technology
casing
The Canon EF was based on the aluminum housing of the Canon F-1, in which the bayonet socket on the underside was bevelled for ergonomic reasons. No motorized film transport could be started.
Viewfinder
In contrast to the F-1, the prism viewfinder could not be exchanged, which, however, was only expected with professional cameras. The ground glass was also permanently installed, originally it consisted of a ground glass with a microprism ring , later models of a ground glass with a micro prism ring and a split image rangefinder . This newer focusing screen also increased the brightness in the viewfinder noticeably.
Film transport
With a single movement, the elevator was tensioned and the film moved on. The elevator lever moved by 120 °. When the film was newly inserted, it was not necessary to press the shutter release every time the elevator moved in order to get to the first picture. Repeated actuation of the elevator until it blocked was sufficient.
There was a button in the main switch for multiple exposures. If you pressed it, the film transport was disengaged and only the shutter was opened with the quick release lever.
Exposure metering
In contrast to the F-1, the exposure measurement was done with a silicon cell. Such a cell worked without inertia even in greater darkness. The measuring range of the Canon EF reached from 30 s at ISO 25/15 ° at f / 1.4 to 1 ⁄ 1000 s at aperture 8. In addition, exposure times of up to 30 s can be set on the shutter speed dial. In order to be able to measure with the very weak current of a silicon cell, the EF had a MOS amplifier IC.
The aperture was indicated with a pointer on the right in the viewfinder and transferred to the lens via the aperture simulator. The set exposure time could also be read on a scale at the bottom of the image in the viewfinder.
The film speed was set on a wheel arranged around the rewind crank, which had a release button and ranged from ISO 12/12 ° to ISO 3200/36 °.
The measured AE values could be fixed. ("AE memory lock")
Auto Shutter AE (Automatic Exposure)
The exposure time could be selected. The aperture was determined from the preselected exposure time and film speed. When the shutter was released, the diaphragm was automatically closed to the value determined by the camera. With the help of a knob on the respective FD lens, the largest possible aperture was communicated to the camera and the under / over exposure warning in the viewfinder was shifted accordingly.
The dial for the shutter speed was made extra large and protruded from the front of the camera housing; it could easily be turned with the right index finger.
Functionality at low temperatures
The camera should remain functional down to −20 ° C (−4 ° F).
Clasp
Just like the F-1, it was a metal focal plane shutter , which, however, ran vertically instead of horizontally and therefore enabled the shortest flash sync time of 1 ⁄ 125 s. In contrast to the F-1, the shortest shutter speed was only 1 ⁄ 1000 s. It was the Copal Square type .
The shutter worked mechanically in the range from 1 ⁄ 2 s to 1 ⁄ 1000 s and then managed without a battery, the longer times of up to 30 s and "B" were implemented by an electronic control. She made a red light emitting diode flash on the top of the housing cover.
Power supply
Like all F-series cameras, the EF also used PX 625 mercury-zinc batteries. It required two of them, for which there were two separate battery compartments in the base plate. Such batteries, which contain more than 25 mg of mercury, were banned in the EU from 1992. Since the electronics had a voltage regulator, they were not, like many other cameras, dependent on the exact 1.35 V of such a mercury battery and also worked perfectly with a 1.5 V button cell. A main switch, the lever of which could be easily turned with the thumb, activated the exposure metering on the right rear of the housing cover. The EF did not have an automatic shutdown of the exposure metering after a certain period of time. That is why the words After using, turn the camera off were placed next to the switch , because the more complex electronics required more power when switched on than many other cameras.
CAT auto flash
Canon EF worked together with the CAT automatic flash, which required the Canon Speedlight 133 D flash unit and the appropriate lens including flash coupler. The camera also automatically set the appropriate aperture. For this purpose, the flash coupler transmitted the set distance from the lens to the flash unit. The flash unit informed the camera of the aperture via two additional contacts in the hot shoe. For the CAT automatic flash, there was a special rotary switch to the left of the viewfinder that was used to activate it.
End of production
The EF was replaced by the Canon A-1 in 1978 . All properties have been retained, including the manually lockable mirror and the metal lock. It was not until 1986 that the T 90 returned to a flash sync time that was shorter than 1 ⁄ 60 s.
After the lower-priced Canon AE-1 appeared in spring 1976, which was also a shutter automat, the EF was hardly bought anymore. Although the AE-1 had to do without some equipment features, in the eyes of most interested parties this was more than offset by the possibility of being able to connect a motorized film transport, a modern system flash and a data back.
Lenses
The EF is suitable for all lenses with the Canon FD bayonet and the much older Canon FL bayonet and Canon R bayonet . Some other lens connections, such as the common M42 lens thread, can also be used on the EF with a suitable adapter.
The convenient TTL exposure metering with open aperture and automatic aperture control is only possible with the FD bayonet. When the EF was launched, the range of Canon FD lenses ranged from 15 mm format-filling fish-eyes to 300 mm telephoto lenses. In addition, there was a 7.5 mm round fisheye and a 1200 mm telephoto. A 2000 mm or 5200 mm reflector telescope lens could also be supplied on request. All later developed Canon FD lenses can also be used with their full functionality.
Almost all of the large, independent lens manufacturers offered their lenses optionally with the FD connection suitable for Canon.
literature
- Canon EF Instructions. English edition. Pub. IE1008F 1174D10, Printed in Japan
- Alexander Decker: Canon automatics - the giant strikes back. In: PhotoDeal , H. 2/2001, p. 4
- Günter Richter: The Canon Reflex System. Laterna Magica publishing house, Munich 1978, ISBN 3-87467-118-6