Since the 1960s, Canon SLRs have had their power switch confusingly labelled as A and L. This has persisted through many different generations of camera and confused beginners through the ages. But what do the letters A and L stand for? Why not use On and Off, or a red dot and a white dot, or a tick and a cross?
First let’s have a look at the switches, starting off with the first ever Canon SLRs, the Canonflex series, which didn’t have any shutter lock at all. The photographer simply had to get into the habit of not winding on until they were ready to shoot, or keeping the camera in a case where the button couldn’t be accidentally pressed.
The first Canon SLRs with a power switch were the FL generation of cameras from the 1960s. These have a rotating collar around the shutter release button with two positions – A and L. This was a physical setting as these cameras had no active electronics in them.
This design was maintained with the introduction of the first generation of FD cameras, the F-series. Some of these cameras had a separate switch on the left hand side to control the light meter. These were labelled On and Off.
Breaking with tradition, the next generation of FD cameras, the A-series in the mid 1970s came along with an unmarked switch close to the shutter release, displaying a red dot when switched off. It looks like an LED, but it’s just a red plastic knobble.
The later half of the A-series from the late 1970s started using a sliding lever near the shutter release, once again returning to the same two positions, A and L. On this AE-1 Program, you can see where the lever has scratched the body with use.
The unashamedly electronic T-series (not a compliment) from the mid 1980s saw a change, and it seems Canon couldn’t decide what to do with the power switch. The consumer-level T70 and T80 used a sliding switch on the top of the camera, but let the secret slip by labelling the switch Lock instead of the usual L. The other settings are the self-timer, and two different metering modes.
The T80 and T90 put the power switch on the back of the camera, using the traditional A and L designations.
The T60 (which is not a true Canon, being made by Cosina) gave a hint of the future by doing away with a power switch entirely and having the A and L positions on the shutter speed dial.
The early EOS film cameras of the late 1980s had a rotating knob on the back with A and L modes, plus other modes on some models.
Apparently the rotating knob idea didn’t work out, as the later EOS film camera series of the 1990s quickly returned to the trend set by the T60, by having an L position on the new command dial – but no A position.
All EOS digital cameras were equipped with an On/Off switch from the very first model back in 2001. The switch varied in position from the back, to next to the shutter release – but never on the command dial.
After this journey spanning five decades of photographic history, are we any closer to knowing what these letters mean? Well, we saw from the T70 that L stands for Lock. But what about A?
Some Canon cameras of the 1970-80s also used A on lenses to designate “auto aperture”, but the Canonflex models of the late 1950s and early 1960s had nothing automatic about them so we can rule out A standing for Auto.
I haven’t been able to find anything online about this, but my theory is that A represents Active or Action, to mean that the camera is ready to shoot. If anyone knows better, please let me know!