Canon AE-1 - Manual (Page 13)

index mark which also serves as battery
charge level check mark. Besides, there are
two red zones at the top of the aperture
scale to warn of overexposure.
Below the aperture scale, a red warning
LED lamp blinks to indicate under­
exposure.This lamp also indicates that the
selected shutter speed is outside the AE
coupling range with respect to the ASA
of the film being used.
Above the aperture scale, a manual
aperture control "M" signal (red LED)
blinks as a warning that the aperture
ring is not set at the "A" mark for AE
photography.
Viewfinder Attachments: Angle Finder A2
and B, Magnifier S, Dioptric Adjustment
Lens (10 kinds), and Eyecup S.
Mirror: Instant-return, large reflector mirror
with shock absorbing mechanism.
AE Mechanism: Shutter priority, electro­
nically controlled AE metering system
incorporating two ICs and one LSI equi­
pped with L (Integrated Injection Logic)
Light Metering System: TTL (Through-
The-Lens) Central Emphasis Metering