Canon EOS Rebel T7i Mode D'emploi De Base page 66

Displaying the Electronic Level
3 Displaying the Electronic Level in the Viewfinder
A simple electronic level using a camera icon can be displayed in the
viewfinder. Since this indicator is displayed during shooting, you can
take the picture while checking the camera tilt.
Electronic level
64
Select [Viewfinder display].
1
Under the [52] tab, select

[Viewfinder display], then press
<0>.
Select [Electronic level].
2
Select [Show].
3
Press the shutter button halfway.
4
 The electronic level will appear at the
position shown in the illustration.
This level also works with vertical

shooting.
Horizontal
Tilt 1°
Tilt 2° or higher