Specifications

22. Flash Photography
Display Information in AE Flash Photography:
Flash Charge-completion Display (with only dedicated Canon
Speedlites 011 A, 155A, 166A, 177A, 188A, 199A, 533G, 577G,
299A and 300 TL etc..)
When the Speedlite is charged and the shutter button is pressed halfway, a green
and the auto working aperture light up in the viewfinder display. After the shutter is
released, the AE-1 PROGRAM switches automatically to normal AE photography
until the pilot lamp and green
glow again.
Note: 1. Except when the shutter speed selector dial is set to "B", the AE- 1 PROGRAM
automatically switches to 1/60 sec. as soon as the Speedlite's pilot lamp and the green
glow.
2. Since the AE-1 PROGRAM displays only full apertures in the viewfinder, the aperture
displayed may be one-half f/stop larger or smaller than the auto working aperture set on
the flash; the auto working aperture is the effective aperture.