Canon EOS-1D X Mark III Advanced User's Manual page 854

2.
Select a part of the bar.
3.
Select a function to assign.
Press <
You can configure advanced settings for functions labeled with
in the lower left of the screen by pressing the <
Note
Default settings can be restored by pressing the <
step 2 displayed. Note that [
if you select [ 9: Clear all Custom Func. (C.Fn)].
> to set it.
6: Custom Controls] settings are not cleared even
854
> button.
> button with the screen in