Canon EOS R6 Mark II Mirrorless Camera with 24-105mm f/4-7.1 Lens - Manual (Page 917)

Note
You can also switch between viewfinder and screen display by pressing a button
you have customized by assigning to switching. With this setting set to [
AUTO1 ] or
[ AUTO2 ], the camera responds to the viewfinder sensor accordingly.
With [ AUTO1 ] set, the camera does not respond to the viewfinder sensor when the
screen is open.
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