An Electronic F-1

The EF was built as an electronic version of Canon's top-of-the line F-1 camera. Because of this, the EF shares the F-1's rugged construction and tough metal body.

Slow speeds from 1 sec. to 30 sec. were electronically-controlled

  with an "impossible to fix" Platinum focal-plane shutter that costs more than the original camera to replace.

The Canon EF is a manual focus 35mm single-lens reflex camera produced by Canon between 1973 and 1978. It was compatible with Canon's FD-mount lenses. 

Similar to the T-90 (1986), it set the benchmark - but was a commercial failure, lasting only a year or so on the market. The Canon EF contained a silicon photocell light meter with a range of EV 18 to EV -2 which measured light in a "central emphasis metering" pattern (also called center weighted average metering) with a bias against the top of the frame, to minimize underexposure due to a bright skyline. The Canon EF could operate "Variable Aperture AE" mode (commonly called shutter priority) or full manual mode, where the operator would control both the shutter speed and the aperture.

Why so costly? The FD used a unique Platinum shutter among Canon's 35mm SLRs; a Copal Square vertical-travel metal blade focal plane shutter. Unusually, long exposures (from 1 second to 30 seconds) were electronically controlled, while shorter ones (1/1000 second to 1/2 second) were mechanically controlled. This was very useful in conserving battery power, and allowed one to use the camera even with dead batteries. The metering system could also be turned off, e.g. when using flash, or at night, to preserve battery life.

Powering the electro-mechanical shutter and light meter were two PX 625 1.35 volt mercury batteries. Because the EF contains a unique voltage control system, common 1.5 volt alkaline batteries can be used in lieu of the now-unavailable mercury ones. The EF is the only camera in the manual focus Canon line of the 1960s and 1970s (which includes the FTb, the F-1, and the FT) that can be used with common 1.5 volt batteries without modification to the internal electronics. Like all pre-1987 Canon SLR's, the EF accepted Canon FD mount lenses. The shutter speed range was 1/1000th of a second to 30 seconds (in a beautifully pedantic touch, the 15 & 30 second settings actually give 16 and 32 seconds, thus preserving the doubling sequence), plus bulb. The X-sync was 1/125th of a second. The camera included setting for film speeds of 12 ASA to 3200 ASA.

The EF also featured a mirror-locking self-timer and a stop-down metering mode which could also be used for depth-of-field preview. The mirror can also be locked up independently of the self-timer for long exposures when the self-timer is not desired.  

  How does the EF work?

The Canon EF is a fully automatic single-lens reflex camera that uses the shutter-speed priority method for setting the exposures. That means, you set the shutter speed and the camera sets the f/stop. The correct f/stop for the selected shutter speed is determined by the extremely sensitive silicon photocells, which measure the incoming light through the lens. With FL lenses the metering is done at the stopped down aperture, when FD lenses are used metering is done at full aperture. The metering system gives more emphasis to the central area of the viewfinder screen and much less to the upper part of the screen. This prevents underexposure of the main picture area if a bright sky is incorporated in the upper part of the picture. The silicon cells do not have a “memory,” as the CDS cells do, that means they respond instantaneously to changes of light intensity under normal lighting conditions. Under extremely dim lighting conditions, however, it takes about five seconds for the meter to adjust itself. Both the pre-selected shutter speed and the electronically selected f/stop are constantly visible in the viewfinder. Most of the modern automatic SLR cameras have these basic features, or at least similar ones, but the Canon EF has some additional features that cannot be found in other automatic SLRs.

   SPECIFICATIONS