Canon Speedlite ST-E10 - Page 61

Setting the flash output and flash exposure compensation amount
Configure flash features available in the flash mode.
For [Manual flash], set the flash output. For [E-TTL II] or
[AutoExtFlash], set the flash exposure compensation amount as
needed.
Repeat step 4 to configure flash features for all firing groups.
Caution
For [AutoExtFlash] flash mode, make sure the receivers support auto external
flash metering. Firing in this flash mode is not possible if auto external flash
metering is not supported.
In [E-TTL II] or [AutoExtFlash] flash mode, exposure is controlled to obtain
standard exposure for the main subject as if using a single group, which may cause
overexposure if multiple firing groups are pointing toward the main subject.
Note
For details on [AutoExtFlash], refer to the instruction manual of flash units that
support auto external flash metering.
The order of firing among firing groups does not need to be consecutive; for
example, A, C, E can be set.
Set any group you do not wish to fire to [Disable] when setting the flash mode in
step 3.
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