Canon EOS 70DN Basic Instruction Manual page 232

Q Displaying the Electronic Level
Even when the tilt is corrected, there may be a margin of error of ±1°.
If he camera is very tilted, the electronic level's margin of error will be
larger.
If he Depth-of-field preview button has been assigned with [VF
electronic level], depth-of-field preview (p.163) will not work.
68
5
Display the electronic level.
Press the Depth-of-field preview
button.
The viewfinder will display an
electronic level and grid using the AF
points.
1°
6° Over