Canon A-1 - Manual (Page 91)

Previewing the Exposure
When you take a meter reading, the view­
finder information will be displayed in a
digital readout directly below the viewing
area. With the viewfinder display lever
switched on, you can take a meter reading in
any one of three ways:
1. Depress the shutter button halfway.
2. Press in the exposure preview switch.
3. Press the exposure memory switch.
Full viewfinder information includes shutter
speed, aperture, manutil aperture control
signal, flash signal, exposure warning flashing
and a flashing error signal for incorrect
operation.
The digital display viewfinder
gives you the most information in a mini­
mum amount of display capacity.
The camera employs LED circuits to elimi­
nate the need for any extra illumination of
viewfinder information. Except when using a
flash or the exposure memory switch when
the LED maintains constant brightness, the