Nikon Z7 - Set Picture Control

77Shooting Controls
3 Choose a shutter speed.
Rotate the main command dial to choose a shutter speed of
Bulb or Time.
4 Open the shutter.
Bulb: After focusing, press the shutter-release button all the
way down. Keep the shutter-release button pressed until the
exposure is complete.
Time: Press the shutter-release button all the way down.
5 Close the shutter.
Bulb: Take your finger off the shutter-release button.
Time: Press the shutter-release button all the way down.
Bulb Time