Nikon 1 J5 Reference Manual page 95

Open the shutter.
3
After focusing, press the shutter-release button all the way
down. Keep the shutter-release button pressed until the
exposure is complete.
4 Close the shutter.
Take your finger off the shutter-release button.
Shooting ends automatically after about two minutes. Note that
some time may be required to record long exposures.
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