Canon MARK IV User Manual (en)

 Shooting Movies
As with normal shooting through the viewfinder, during movie shooting, 
you can still use the camera buttons to change function settings and 
execute playback.
Pressing the <W>, <o>, 
<O> or <A> button will display the 
respective setting screen on the LCD 
monitor. To change the setting, turn the 
<6> or <5> dial.
When you press the <B> button, turn the <6> dial to set the 
card to be used to record and turn the <5> dial to set the image 
size or white balance while looking at the rear LCD panel.
The metering mode will be fixed to center-weighted average 
metering for movie shooting. If the AF mode is set to [u (Face 
detection) Live mode
], the exposure control will be evaluative 
metering linked to the detected face.
Even if the AF mode has been set to [Quick mode], it will switch to 
[Live mode] during movie shooting.
For continuous shooting of still photos during movie shooting, using a 
high-speed CF card compatible with UDMA transfers is recommended. 
Setting a smaller image size for still photos and shooting fewer 
continuous still photos are also recommended.
If the drive mode has been set to <k> or <l> and you start shooting 
a movie, the drive mode will automatically change to <u> (single 
Shooting Function Settings