Nikon D780 Reference Manual page 232

A
Mirror-Up Mode
•
Use of a tripod is recommended.
•
To prevent blurring caused by camera movement, press the shutter-
release button smoothly.
•
The mirror lowers when shooting ends.
•
A picture will be taken automatically if no operations are performed for
about 30 s after the mirror is raised.
•
In live view, the picture is taken the first time the shutter-release button
is pressed all the way down.
186 Shooting Settings