Nikon D780 Reference Manual page 340

D
NEF (RAW)
Multiple exposures shot with an NEF (RAW) or NEF (RAW) + JPEG option
selected for image quality will be recorded in JPEG format.
D
Multiple Exposure
•
If the monitor turns off during playback or menu operations and no
operations are performed for about 30 s, shooting will end and a
multiple exposure will be created from the exposures that have been
recorded to that point. The time available to record the next exposure
can be extended by choosing longer times for Custom Setting c2
[Standby timer].
•
Multiple exposures may be affected by noise (randomly-spaced bright
pixels, fog, or lines).
•
In continuous shooting modes, the camera records all exposures in a
single burst. If [On (single photo)] is selected, multiple exposure
shooting will end after the first multiple exposure is recorded. If [On
(series)] is selected, an additional multiple exposure will be recorded
each time the shutter-release button is pressed.
•
In self-timer mode ( 0 183), the camera will automatically record the
number of exposures selected in Step 3, regardless of the option
selected for Custom Setting c3 [Self-timer] > [Number of shots]; the
interval between shots is however controlled by Custom Setting c3
[Self-timer] > [Interval between shots].
•
The shooting settings and photo info for multiple exposure
photographs are those for the first exposure.
•
Do not remove or replace the memory card while recording a multiple
exposure.
•
While a multiple exposure is being shot, memory cards cannot be
formatted and some menu items are grayed out and cannot be
changed.
294 Other Shooting Options