Canon MARK IV User Manual (en)

Custom Function Settings
C.Fn IV -6     Dial direction during Tv/Av
0: Normal
1: Reverse direction
The dial’s turning direction for setting the shutter speed and aperture 
can be reversed.
In the manual exposure mode, the direction of the <6> and <5> 
dials will be reversed. In other shooting modes, the <6> dial will be 
reversed. The <5> dial’s turning direction will be the same for the 
manual exposure mode and exposure compensation.
C.Fn IV -7     Av setting without lens
0: Disable
1: Enable
You can set the aperture with the camera even while the lens is 
detached. For studio photography when the aperture is already 
determined, you can set the aperture beforehand.
C.Fn IV -8     WB + media/image size setting
When you press the <B> button to select or set the white balance, 
card, or image size, you can choose to do it with the rear LCD panel or with 
the menu screen.
0: Rear LCD panel
1: LCD monitor
When you press the <B> button, the menu screen will appear. Each 
time you press the button, the screen will change to display the [White 
], [Image size], and [Record func+media/folder sel.].
Even with setting 1, if you press the <B> button during Live View or 
movie shooting, you can set the settings above while looking at the rear 
LCD panel.