Canon EOS 250D Advanced User's Manual page 454

C.Fn-11 Retract lens on power off
This is the setting for the lens retraction mechanism when a gear-driven
STM lens (such as EF40mm f/2.8 STM) is attached to the camera. You can
set it to retract the extended lens automatically when the camera's power
switch is set to <2>.
0: Enable
1: Disable
With auto power off, the lens will not retract regardless of the setting.
z
Before detaching the lens, make sure that it is retracted.
z
With setting 0, this function takes effect regardless of the lens's focus mode
z
switch setting (AF or MF).
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