Canon EOS-1D X Mark III DSLR Camera (Body Only) - Manual (Page 114)

4.
Focus on the subject.
(1) Standard exposure index
(2) Exposure level mark
(3) Brighter (+)
(4) Darker (−)
Press the shutter button halfway.
The exposure value is displayed in the viewfinder and on the top LCD
panel.
To see how far the current exposure level < > is from standard
exposure < >, check the exposure level indicator at right in the
viewfinder.
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