Canon EOS 90D DSLR Camera with 18-135mm Lens - Manual (Page 187)

187
Wireless Flash Photography Using Optical Transmission
Autofl ash With Multiple Receivers and a Sender
You can include a sender in the wireless fl ash photography arrangements
described from = 185 to = 186.
1 Set these basic settings.
Flash mode : E-TTL II
Wireless functions :
0
+
3
Channel : (same as receiver)
2 Set [Firing group].
 Select [
1
All and
2
] or [
1
(A:B)
2
] .
 Before shooting with [
1
(A:B)
2
] , set
the A:B fl ash ratio.
[
1
All and
2
]
A B
[
1
(A:B)
2
]