Canon EOS M Instruction Manual page 38

Turning on the Power
3 Power-saving Features
To save power, the LCD monitor turns off automatically if you do not
operate the camera. If you continue to not operate the camera, the
power will turn off automatically. While the LCD monitor is off,
pressing any camera button or tapping the LCD monitor will turn it on
again. If the power turned off, either press the power button or press
the <x> for at least approx. 2 sec. to turn on the power again.
You can change the LCD monitor auto off time and Camera auto off
time with [LCD auto off] and [Camera auto off] under [52: Power
saving] (p.206).
If you set the power to <2> while an image is being recorded to the card,
[Recording...] will be displayed and the power will turn off after the card
finishes recording the image.
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