Canon EOS 80D - Manual (Page 74)

74
If you set this function, will appear in the viewfinder when
the camera detects flicker caused by the blinking of the light source. By
default, flicker detection is set to [Show].
1
Select [Viewfinder display].
 Under the [52] tab, select
[Viewfinder display], then press
<0>.
2
Select [Flicker detection].
3
Select [Show].
Displaying the Flicker DetectionN
If you set [z4: Anti-flicker shoot.] to [Enable], you can shoot with
reduced unevenness of exposure caused by the flicker (p.179).