Nikon D5100 Reference Manual page 14

I I Interrupting Multiple Exposures
To interrupt a multiple exposure before the specified number of
exposures have been taken, select Off for Multiple exposure >
Multiple exposure mode in the shooting menu. A multiple
exposure will be created from the exposures that have been
recorded to that point. If Auto gain is on, gain will be adjusted
to reflect the number of exposures actually recorded. Note that
shooting will end automatically if:
• The mode dial is rotated to a setting other than P,S,A, or M
• A two-button reset is performed (_ 58)
• The camera is turned off
• The battery is exhausted
• One of the exposures is deleted
i_ Multiple Exposures
Do not remove or replace the memory card while recording a multiple exposure.
The information listed in the playback photo information display (including metering,
exposure, shooting mode, focal length, date of recording and camera orientation) is for the
first shot in the multiple exposure.
8O