Canon Speedlite 600EX-RT Instruction Manual page 45

Settings Available in [Flash function settings]
EOS digital cameras released since 2012
When using the flash with cameras such as EOS-1D X, you can set the
functions for "Normal shooting", "Radio transmission wireless shooting"
or "Optical transmission wireless shooting" in the [Flash function
settings] screen.
EOS digital cameras released from 2007 to 2011
You can set the functions for "Normal shooting" or "Optical transmission
wireless shooting" in the [Flash function setting] screen. To use
"Radio transmission wireless shooting", set the functions by operating
the flash.
The settable functions are as follows. The available settings vary
depending on the flash mode or wireless function setting.
Flash firing
E-TTL II flash metering Evaluative / Average
Flash synchronization speed in Av mode
Flash mode
Shutter
synchronization
Flash exposure compensation
FEB
Zoom (flash coverage)
Wireless functions
(setting)
Clear Speedlite function settings
[Flash firing] and [E-TTL II flash metering] are displayed in step 2 or
step 3 on the preceding page (depending on the camera).
When [Flash sync. speed in Av mode] is not displayed, it can be set
with the camera's Custom Function.
Flash Control from Camera's Menu Screen
Function
Enable / Disable
E-TTL II (autoflash) / Manual flash /
MULTI flash / Auto external flash
metering / Manual external flash
metering / TTL (autoflash)
1st curtain / 2nd curtain / Hi-speed
Radio transmission wireless /
Optical transmission wireless
Reference Page
p.44
p.45
43