Canon Speedlite 600EX-RT Mode D'emploi page 48

Flash Control from Camera's Menu Screen
Flash Custom Function Settings
The displayed contents vary depending on the camera. When C.Fn-20
to 23 are not displayed, set them by operating the flash unit. For the
Custom Functions, see pages 95 to 100.
When using a camera released up to 2011 or EOS REBEL T5/EOS
1200D, the C.Fn-20 to 23 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 94, all the Custom Functions
(except C.Fn-00) are cleared.
When using the flash with EOS digital cameras released since 2012, as
auto external metering and manual external metering can be
automatically selected with the flash's <E> button, C.Fn-05-2, 3 are
not selectable (except with EOS REBEL T5/EOS 1200D).
You cannot set or clear all Personal Functions (P.Fn/p.101) from the
camera's menu screen. Set them by operating the flash unit.
46
Select [Flash C.Fn settings].
1
Select [Flash C.Fn settings] or
[External flash C.Fn setting].
The screen changes to the (external)
flash Custom Function settings
screen.
Set the Custom Function.
2
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.