Canon C12-8453, Service Manual

Page: 33 / 271

11-5 Auto flash operation: In Program AE Mode
(1) With EX-series Speedlites: E-TTL autoflash
1) Normal flash
When the flash is ready, the sync speed (1/60 to 1/125 sec.) is
set automatically and the flash aperture is set automatically by
the camera’s E-TTL program. When the shutter button is
pressed completely, a fixed-output preflash is fired right before
the mirror goes up. The AE sensor meters the ambient light
before the preflash and the light reflected off the subject by the
preflash. The output of the main flash is thereby determined
before the main flash fires. The main flash then fires. If the
EX-series Speedlite’s high-speed sync (FP flash) switch is on and
the brightness is still too high for the smallest aperture, the
high-speed sync mode is set automatically. When high-speed
sync is set, the
icon lights in the viewfinder. Automatic fill-
in flash is possible.
2) FE lock
When an EX-series Speedlite is attached and the flash is ready,
the AE lock button becomes an FE lock button. Pressing the AE
lock button fires a preflash. The AE sensor, with partial
metering, reads the preflash light reflected off the subject. The
flash output is thereby determined and retained in memory.
When the shutter button is pressed completely, the flash fires at
the output retained in memory. If the EX-series Speedlite’s
high-speed sync (FP flash) switch is on and the brightness is
still too high for the smallest aperture, high-speed sync mode is
set automatically. When high-speed sync is set, the
icon
lights in the viewfinder. When the FE lock button is pressed and
the flash is ready, a preflash is fired and FE lock takes effect. If
the flash will be insufficient (underexposure exceeds by more
than 0.5 stop compared to the correct flash exposure), the
icon blinks as a warning before the picture is taken.
Automatic fill-in flash is possible.
(2) With built-in flash:TTL autoflash
When the flash is ready, the sync speed (1/60 to 1/125 sec.) is
set automatically and the aperture is set automatically by the
camera’s TTL program. TTL off-the-film autoflash control with
3-zone flash metering linked to focusing point. Automatic fill-in
flash is possible.
(3) With EZ/E-series Speedlite: A-TTL autoflash
When the flash is ready, the sync speed (1/60 to 1/125 sec.) is
set automatically and the optimum flash aperture is set
automatically by the camera’s A-TTL program and the result of
the Speedlite’s near-infrared preflash to suit the subject’s
distance and brightness. TTL off-the-film autoflash control with
3-zone flash metering linked to the focusing point. Automatic
fill-in flash is possible.
(4) With the ML-3 and 480EG: TTL autoflash metering
→
Same as (2).
* For (1) to (4) above, a sync speed of 1/125 sec. or slower can
be set when the camera is set to shutter speed-priority AE.
Also, when an EX-series Speedlite is attached and the
high-speed sync (FP flash) switch is on, a sync speed faster
than 1/125 sec. can be set. In the aperture-priority AE mode,
any aperture can be selected.
(5) With M/T/A-series Speedlites:
Manual or external flash metering required.
* Picture-taking mode: Manual
* Sync speed: Set manually to 30 sec. to 1/125 sec. or bulb.
* Flash aperture: Set the same aperture value manually on the
camera and Speedlite.
Part 1: General Information
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