Canon ST-E3-RT-V2 Manual page 54

Transmitter Control from Camera's Menu Screen
Transmitter Custom Function Settings
The displayed contents vary depending on the camera. If C.Fn-20 and
22 are not displayed, set them by operating the transmitter. For the
Custom Functions, see pages 58 to 59.
When using a camera released up to 2011 or EOS REBEL T100/4000D/
3000D, EOS REBEL T7/1500D/2000D, EOS REBEL T6/1300D and EOS
REBEL T5/1200D, the C.Fn-20 and 22 settings are not cleared even if
[Clear all Speedlite C.Fn's] is selected. When following the "Clearing All
the Custom Functions" operation on page 57, all the Custom Functions are
cleared.
You cannot set or clear all Personal Functions (P.Fn/p.60) from the camera's
menu screen. Set them by operating the transmitter.
54
1
Select [Flash C.Fn settings].
Select [Flash C.Fn settings] or

[External flash C.Fn setting].
You can now set the Custom
Functions of the transmitter.
2
Set the Custom Function.
Select the Custom Function number

and set the function.
To clear all the Custom Function

settings, select [Clear all Speedlite
C.Fn's] or [Clear ext. flash C.Fn
set.] in step 1.