The Canon EOS 7D was the first EOS camera to feature a Dual Axis Electronic Level - a feature that is capable of indicating an alignment level for both pitch and roll on the rear LCD screen and within the viewfinder.
This is particularly useful for landscape photographers to ensure level horizons and for photographers shooting with tilt and shift lenses who need to level the pitch of the camera to ensure that verticals are captured vertically. It will also prove useful in low light where it is hard to see reference points that would otherwise give you an indication of whether the horizon is level or not.
Accessing the electronic level is done via pressing the INFO button. This will display 360° of roll and +/-10° of pitch in 1° increments. When in Live View Mode a smaller display is overlaid on top of the image. The electronic level is accurate to +/-1° at up to +/-10°. Between +/-10° and +/-45° the accuracy is +/-3°.
When using the viewfinder the electronic level is displayed using different combinations of the AF points. The viewfinder can display +/-6° of roll and +/-4° of pitch in 1° increments. If the camera is held vertically the viewfinder will then display +/-6° of pitch and +/-4° of roll.
A Dual Axis Electronic Level is featured on the following Canon DSLR cameras: EOS 7D, EOS 60D, EOS 5D Mark III, EOS-1D X.