Nikon D780 DSLR Camera (Body Only) - Manual (Page 231)

185 Shooting Settings
Mirror up Mode (M
UP
)
Choose this mode to minimize blurring caused by camera
movement when the mirror is raised. To use mirror-up mode,
press the release mode dial lock release and rotate the release
mode dial to
M
UP
(mirror up). After pressing the shutter-release
button halfway to set focus and exposure, press the shutter-
release button the rest of the way down to raise the mirror.
Z
will be displayed in the control panel; press the shutter-release
button all the way down again to take the picture.
D Mirror Up
While the mirror is raised, photos cannot be framed in the viewfinder and
autofocus and metering will not be performed.