Canon AE-1 - Manual (Page 106)

Canon Speed life 155A
The versatile circuitry of the Canon AE-1
allows it to perform fully automatic flash
photography with the Speedlite 155A es­
pecially designed for this camera. It is not
necessary to set the shutter speed or the
aperture on the camera as, up to now, flash
photography required.
When the 155A is attached to the AE-1,
set the aperture ring of the lens to the "A"
mark and the shutter speed dial to any
position other than "B" (Bulb). With the pilot
lamp of the 155A lighting up, the 155A func­
tions to automatically adjust the camera's
shutter speed to the X synchronization speed
as well as the aperture to the prescribed
f/stop value.
After it flashes, the camera automatically
switches over to the AE photography mode
until the pilot lamp lights up again during
which period AE photography can be con­
tinued. A steady support may be required if
shutter speeds are slower than 1/30 of a
second.
Like ordinary flash units, you can also
perform flash photography by operating the