Canon 155 A - Manual (Page 9)

Main Features
1. The aperture selected on the 155A is set
on the camera automatically via an
electrical signal sent by the flash (in the
case of the AE-1 and A-1).
2. In the same way, the light output signal
from the 155A automatically sets the
shutter speed of the camera to 1/60
sec. (X contact).
3. Battery consumption is reduced with the
employment of the series control system.
4. Average distribution metering is ob­
tained by suppressing the peak sensitivity
at the center of the picture.
5. When the main switch of the flash is at
OFF, the camera returns to normal
non-flash AE photography while the 155 A
is still attached to the camera.
6. Manually operated flash by cancelling the
automatic flash is possible.