Canon MARK IV User Manual (en)

<2> : The camera is turned off and 
does not operate. Set to this 
position when not using the 
<1> : The camera turns on.
: The camera and <5> operate 
Whenever you set the power switch to 
<1/J> or <2>, the sensor 
cleaning will be executed automatically. 
During the sensor cleaning, the LCD 
monitor will display <f>.
Even during the sensor cleaning, you 
can still shoot by pressing the shutter 
button halfway (p.41) to stop the 
sensor cleaning and take a picture.
If you turn on/off the power switch 
<1/J>/<2> at a short interval, 
the <f> icon might not be displayed. 
This is normal and not a problem.
To save battery power, the camera turns off automatically after 
approx. 1 minute of non-operation. To turn on the camera again, just 
press the shutter button halfway (p.41).
You can change the auto power-off time with the menu’s [5 Auto 
power off
] setting (p.52).
Turning on the Power
Power/Quick Control Dial Switch
About the Automatic Self-Cleaning Sensor
About Auto Power Off
If you set the power switch 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.