Canon AE-1 Manual page 34

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 underexposure. 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.
AE Mechanism: Shutter priority, electronically controlled AE metering system incorporating
two ICs and one LSI equipped with
Light Metering System: TTL (Through-the-Lens) Central Emphasis Metering method
employing a Silicon Photocell as photosensitive element.
Exposure Meter Coupling Range: With ISO 100 film, EV1 (f/1.4 at one second) to EV18
(f/16 at 1/1000 second).
Film Speed Range: ISO 25 to ISO 3200.
Exposure Correction: By pressing the backlight control switch, exposure is corrected by the
automatic opening of the diaphragm 1.5 stops more on the aperture scale than the actual
setting.
Exposure Preview: The meter needle will indicate in the viewfinder when the shutter release
button is depressed halfway or the exposure preview switch is depressed.
Shutter: Cloth focal plane shutter with four spindles. Shock and noise damping mechanisms
are incorporated. All shutter speeds are electronically controlled.
Shutter Speeds: 1 /1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, 1/4, 1/2, 1, 2 (seconds)
and B. X synchronization is at 1/60 seconds.
Shutter Speed Dial: The shutter speed dial is on the same axis as the film advance lever. The
number 2 for two seconds is marked in orange; other numbers as well as X synchronization
are in white. There is a shutter dial guard to prevent unintentional movement of the dial. The
ISO dial is located underneath the shutter speed dial.
Shutter Release Button: It is a large, button type magnetic release switch. Depressing the
shutter release button halfway switches on the light metering circuit, while full depression
releases the shutter. The shutter release button has a locking device, besides a socket for the
cable release in the center.
Self-Timer: Electronically controlled self timer. After the self-timer lever is pushed forward,
the self-timer is activated by the shutter release button. The self-timer releases the shutter after
a time lag of 10 seconds. A self-timer lamp (red LED) blinks on and off to indicate when the
self-timer is in operation.
Stopping-Down the Lens Stopping-down the lens can be performed by pushing the stopped-
down lever after setting the aperture ring.
Power Source: One 6V silver oxide battery Eveready No.544, UCAR No.544 JIS 4G 13, or
Mallory PX28) or alkaline manganese battery (Eveready No.537, UCAR No.537, or Mallory
7K13). The battery lasts approximately one year under normal use.
Battery Check: Battery power level can be checked by the meter needle in the viewfinder
Viewfinder Information:
Split- image/microprism rangefinder, aperture scale with
meter needle and stopped-down metering index mark
which also serves as battery charge level check mark.
(Integrated Injection Logic)