Canon EOS 7D Instruction Manual page 128

Using Wireless FlashN
[1 (A:B)] Multiple slave units in multiple groups
Indoors
A
Outdoors
The 8:1 to 1:1 to 1:8 flash ratio is equivalent to 3:1 to 1:1 to 1:3 stops (1/2-
stop increments).
128
Approx. 10m
(32.8ft.)
Approx. 7m
(23.0ft.)
o
80
5m (16.4ft.)
1
Set [Firing group] to [1 (A:B)].
2
Set the desired flash ratio and
shoot.

Divide the slave units into
groups A and B, and change
the flash ratio to obtain the
desired lighting effect.
Approx.
Refer to your Speedlite's
7m
B
instruction manual to set one
(23.0ft.)
slave unit's slave ID to A
Approx.
(Group A) and the other
slave unit's ID to B (Group
B) and position them as
shown in the illustration.
Select [A:B fire ratio] and set the
flash ratio.