Nikon D780 Reference Manual page 806

"Noise" (bright spots, randomly-spaced bright pixels, fog, or
●
lines) appears during live view:
•
Randomly-spaced bright pixels, fog, or bright spots may arise as a
result of increases in the temperature of the camera's internal
circuits during live view. Exit live view when the camera is not in use.
•
Randomly-spaced bright pixels, fog, lines or unexpected colors may
appear if you press the X ( T ) button to zoom in on the view
through the lens during live view.
•
In movies, the amount and distribution of randomly-spaced bright
pixels, fog, and bright spots are affected by the option selected for
[Frame size/frame rate] in the movie shooting menu.
•
Note that the distribution of noise in the monitor may differ from
that in the final picture.
The camera cannot measure a value for preset manual white
●
balance:
The subject is too dark or too bright.
Certain pictures cannot be selected as sources for preset white
●
balance:
Pictures created with cameras of other types cannot serve as sources
for preset manual white balance.
760 Troubleshooting