Canon EOS-1D X Mark III DSLR Camera (Body Only) - Manual (Page 230)

3.
Take the picture.
To cancel exposure compensation, set the exposure level < / > to
the standard exposure index (< / >).
Caution
If [ : Auto Lighting Optimizer ] ( ) is set to any setting other than [ Disable ], the
image may still look bright even if decreased exposure compensation is set to
darken images.
Note
Can also be set by pressing the < > button and turning the < > or < >
dial.
The exposure compensation amount will remain in effect even after you set the
power switch to <
>.
To prevent accidental changes to the exposure compensation amount after setting
it, set the power switch to <
>.
If the exposure compensation amount exceeds ±3 stops, the end of the exposure
level indicator will display < /
> or < / >.
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