Canon EOS-1D X Mark III Advanced User's Manual page 850

C.Fn8
Default Erase option
You can set which option is selected by default in the erase menu (
by pressing the <
By setting an option other than [Cancel], you can simply press <
quickly.
: [Cancel] selected
: [Erase] selected
: [Erase
: [Erase non-
Caution
Be careful not to erase images accidentally when an option other than [Cancel] is
set.
Retract lens on power off
You can set whether to retract gear-type STM lenses (such as EF40mm f/2.8 STM)
automatically when the camera's power switch is set to <
ON: Enable
OFF: Disable
Caution
With auto power off, the lens will not retract regardless of the setting.
Before detaching the lens, make sure that it is retracted.
Note
When [Enable] is set, this function takes effect regardless of the lens's focus mode
switch setting (AF or MF).
> button during image playback or during review after shooting.
] selected
] selected
>.
850
), which is accessed
> to erase images