CANON EF

Name: Canon EF
Brand: Canon

The Canon EF came out in 1973. It was Canon's first electronically controlled, shutter-priority automatic exposure (AE) 35mm single-lens reflex (SLR) camera. It used the newly developed FD lens mount and a vertical-travel metal focal-plane shutter. For Canon, it was a step from fully mechanical SLRs toward electronically integrated ones.

Overview

The Canon EF was launched at a pivotal moment in the evolution of 35mm photography, as manufacturers began integrating electronic automation into SLR design. Positioned above the manual-exposure FTb and below the professional F-1 in Canon’s lineup, the EF targeted advanced amateur and semi-professional photographers seeking automated exposure without sacrificing build quality. Unlike the modular, mechanically driven F-1, the EF emphasized ease of use through shutter-priority autoexposure, making it one of the earliest Japanese SLRs to offer this feature in a mass-market body.

The shutter is a newly designed Copal Square vertical-travel metal unit. Speeds run from 1 second to 1/1000 second, with flash sync at 1/60 second. The vertical design allowed a more compact mechanism and faster flash sync than traditional horizontal cloth shutters. The EF used the new breech-lock Canon FD mount, which gave full-aperture TTL (through-the-lens) metering with FD-series lenses. Metering was center-weighted and coupled to the shutter speed selector. You set the shutter speed, and the camera picked the correct aperture through the lens's meter coupling lever.

For all its electronics, the EF kept a good deal of mechanical reliability. Manual shutter speeds were available down to 1 second, and there was a mechanical Bulb mode for long exposures. The pentaprism viewfinder gave a bright, clear image, with a split-image rangefinder and microprism collar for focusing. The chassis is die-cast aluminum and the construction is rugged, so Canon kept durability even in an electronically augmented model.

Specifications

Specification	Value
Type	35mm Single-Lens Reflex (SLR)
Film Format	35mm (135 film)
Years Produced	1973–1978
Lens Mount	Canon FD (breech-lock)
Shutter	Copal Square vertical-travel metal focal-plane shutter; speeds 1s – 1/1000s, plus Bulb (B)
Metering	TTL full-aperture center-weighted metering with CdS cell
Exposure Modes	Shutter-priority AE, Manual (via stop-down metering)
Viewfinder	Fixed pentaprism with split-image rangefinder, microprism collar, and frame coverage ~97%
Dimensions	148 × 95 × 55 mm; Weight: ~705 g (body only, no battery)

Key Features

Shutter-priority automatic exposure: One of the first Japanese SLRs to offer this mode, allowing photographers to set shutter speed while the camera selected the correct aperture.
Vertical metal focal-plane shutter: The Copal Square shutter enabled faster flash sync (1/60s) and improved durability over traditional cloth shutters.
FD lens mount with full-aperture metering: Enabled seamless integration with Canon’s new FD-series lenses for accurate TTL exposure.
Electronic shutter control: Utilized a CMOS IC circuit for precise timing, powered by two 1.5V 2CR5 lithium batteries.
Manual override and stop-down metering: Allowed use of non-FD lenses and precise control in challenging lighting.

Historical Context

The Canon EF was introduced in March 1973, just months after the flagship Canon F-1. It was Canon's move to expand the FD system into semi-automatic territory. At the time Nikon dominated the professional SLR market with the Nikon F and its sturdy mechanical design, while Minolta and Pentax were starting to explore electronic automation. The EF predated Minolta's XD series (1977), which later offered both aperture- and shutter-priority modes.

The EF competed directly with models like the Topcon RE Super D, which offered similar shutter-priority automation, and the later Olympus OM-2 (1975). The OM-2 used aperture-priority and a horizontal cloth shutter. A vertical metal shutter was relatively rare then, shared only with high-end models like the Nikon F2S (with Electromax shutter). Canon's EF made that technology available to a broader market.

The EF had a fairly short production run, ending in 1978. Its successor was not a direct upgrade but the A-series (AE-1, A-1, etc.), with more advanced electronics, aperture-priority metering, and eventually program modes. The short life was due in part to fast advances in microprocessor technology, which made more compact and feature-rich designs possible by the late 1970s.

Collectibility & Value

Today the Canon EF is sought after by collectors of vintage electronic SLRs, particularly those interested in the evolution of Canon's FD system. It isn't as widely collected as the F-1 or the later AE-1, due to its lower production numbers and niche positioning. Collectors value it as Canon's first AE SLR and for its Copal Square shutter.

In the current market (2024), a fully functional Canon EF in good cosmetic condition typically sells for $250 - $400, depending on included accessories and lens. Models with original boxes, manuals, or rare variants (such as early black-chrome prototypes) can command higher prices. Check that the shutter operates correctly across all speeds and that the meter still responds, as the CdS cell can degrade over time. The 2CR5 battery compartment is prone to corrosion, and original batteries are obsolete, though modern equivalents (e.g., two 1/2AA lithium cells in a holder) are available.

Common issues include sticky shutter curtains (especially if stored improperly), worn shutter speed contacts, and degraded light seals. The EF relies on electronic timing circuits, so repairs often need specialized knowledge of 1970s-era CMOS logic systems. That makes servicing more complex than on fully mechanical cameras.

Similar Cameras

Minolta XE (1974) – Jointly developed with Leica, offered both aperture- and shutter-priority modes with a robust mechanical shutter.
Nikon Nikkormat EL (1972) – Nikon’s first shutter-priority AE SLR, using a horizontal cloth shutter and Nikon F-mount.
Olympus OM-2 (1975) – Aperture-priority SLR with TTL OTF metering and a compact design.
Pentax ES (1971) – Early Japanese shutter-priority SLR with a Copal horizontal shutter and M42 screw mount.
Topcon RE Super D (1973) – One of the first shutter-priority SLRs, featuring a unique mechanical-electronic hybrid system.

Repair & Maintenance

The Canon EF requires two 1.5V 2CR5 lithium batteries (or modern substitutes) to power its CMOS-based shutter control circuit and light meter. They sit in a compartment on the baseplate and are prone to leakage if left installed for extended periods. The light seals should be replaced during restoration to prevent light leaks and sticky mirror dampers.

Common mechanical issues include shutter lag at slow speeds, inconsistent 1/1000s performance, and failure to fire in AE mode due to worn contacts or degraded ICs. The meter coupling lever and aperture signal lever on the lens mount must move freely for accurate exposure. Servicing the Copal Square shutter takes precision tools and experience, as the vertical metal blades are tightly integrated. The EF's hybrid electronic-mechanical design makes it harder to repair than fully mechanical SLRs, and replacement parts are scarce. Regular use and removing the batteries during storage are recommended to maintain long-term functionality.