Canon EOS REBEL T7i Instruction Manual page 394

3 Custom Function Setting ItemsN
C.Fn-8
You can set whether or not to display the AF point(s) in the following
cases: 1. when selecting the AF point(s), 2. when the camera is ready
to shoot (before AF operation), 3. during AF operation, and 4. when
focus is achieved.
0: Selected (constant)
The selected AF point(s) is always displayed.
1: All (constant)
All the AF points are always displayed.
2: Selected (pre-AF,focused)
The selected AF point(s) is displayed for 1, 2, and 4.
3: Selected AF pt (focused)
The selected AF point(s) is displayed for 1 and 4.
4: Disable display
For 2, 3, and 4, the selected AF point(s) will not be displayed.
With setting 2 or 3, the AF point will not be displayed even when focus is
achieved with AI Servo AF.
C.Fn-9
You can set whether the AF points in the viewfinder will light up in red
when focus is achieved.
0: Auto
The AF points automatically light up in red under low light.
1: Enable
The AF points light up in red regardless of the ambient light level.
2: Disable
The AF points do not light up in red.
When AI Servo AF is set, the AF points will not light up in red even when
focus is achieved.
When you press the <S> or <B> button, the AF points will be

illuminated in red regardless of this setting.
The aspect ratio lines (p.150), and the electronic level, grid, and flicker

detection set with [52: Viewfinder display] will also light up in red.
394
AF point display during focus
Viewfinder display illumination