Nikon D6 Reference Manual page 120

D
The Count-Down Display
A count down will appear in the top left corner of the display
approximately 30 s before live view ends automatically.
•
If the timer has been triggered by Custom Setting c4 [Monitor off
delay], the count down will be displayed in black starting 30 s before
the timer expires, switching to red when there are only 5 s to go. If [No
limit] is selected for [Monitor off delay] > [Live view], the camera may
nevertheless terminate live view as necessary to protect its internal
circuits from high temperatures and the like.
•
A count down will be displayed in red starting 30 s before the camera
shuts down to protect its internal circuits. Depending on shooting
conditions, the timer may appear immediately when live view is
selected.
•
Note that regardless of the time available (displayed in the top right
corner of the monitor), live view and movie recording will end
automatically when the count-down timer expires.
D
Adjusting Settings During Movie Recording
•
Headphone volume cannot be adjusted during recording.
• If an option other than I (microphone off) is currently selected,
microphone sensitivity can be changed while recording is in progress. I
cannot be selected.
68
Recording Movies