Canon EOS 7D Instruction Manual page 123

Fully-automatic Shooting with Multiple External Speedlites
Multiple Speedlite slave units can be treated as one flash unit or
separated into slave groups whose flash ratio can be set.
The basic settings are shown below. By changing the [Firing group]
setting, you can shoot with various wireless flash setups with multiple
Speedlites.
[1 (A+B+C)] Using multiple slave Speedlites as one flash unit
Indoors
Outdoors
Basic settings:
Flash mode
E-TTL II
Wireless func. : 0
Channel
Approx. 10m
(32.8ft.)
Approx. 7m
(23.0ft.)
Approx.
o
80
5m (16.4ft.)
Set [Firing group] to
[1 (A+B+C)], then shoot.
: E-TTL II
: Evaluative
: (Same as slave units)
Convenient when you need a
large flash output. All the
slave Speedlites will fire at the
same output and controlled to
Approx.
obtain a standard exposure.
7m
No matter what the slave ID is
(23.0ft.)
(A, B, or C), all the slave units
will fire as one group.
Using Wireless FlashN
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