Canon EOS 90D Advanced User's Manual page 183

Wireless Flash Photography Using Optical Transmission
4
Set to [Flash mode: E-TTL II].
5
Set [Wireless func.] to [0].
6
Confi gure [Channel].
Set the same optical channel (1–4) as

the receiver.
7
Set [Firing group] to [1All].
8
Take the picture.
Just as in normal fl ash photography,

shoot after confi guring the camera.
To stop wireless fl ash photography, set

[Wireless func.] to [Disable].
183