Nikon Z 50 Reference Manual - Page 261

Ending Multiple Exposures To end a multiple exposure before the specified number of exposures have been taken, select Off for Multiple exposure mode or press the K button followed by the i button and select either Save and exit or Discard and exit. If shooting ends or you select Save and exit before the specified number of exposures have been taken, a multiple exposure will be created from the exposures that have been recorded to that point. If Average is selected for Overlay mode, gain will be adjusted to reflect the number of exposures actually recorded. Note that shooting will end automatically if the standby timer expires. D The Standby Timer Menus and playback can be used between exposures, but note that if no operations are performed for about 40 seconds during playback or 90 seconds while menus are displayed, shooting will end and a multiple exposure will be created from the exposures recorded to that point. The time available to record the next exposure can be extended by choosing longer times for Custom Setting c3 (Power off delay) > Playback and Menus. Menu Guide > C The Photo Shooting Menu 233