Canon EOS R3 Advanced User's Manual page 129

2.
Set the desired shutter speed.
Turn the <
3.
Focus on the subject.
Press the shutter button halfway.
The aperture value is set automatically.
4.
Check the display and shoot.
As long as the aperture value is not blinking, the standard exposure will
be obtained.
Caution
If the lowest aperture value blinks, it indicates underexposure.
Turn the < > dial to set a slower shutter speed until the aperture value stops
blinking or set a higher ISO speed.
If the highest aperture value blinks, it indicates overexposure.
Turn the < > dial to set a faster shutter speed until the aperture value stops
blinking, or set a lower ISO speed.
> dial to set it.
129