Multiple fireworks rockets explode in the night sky. Image brightness for fireworks photography is completely determined by the aperture setting since the rockets and explosions are never still. I sometimes use a neutral density filter when photographing fireworks to allow a wider aperture to be used (for sharper images due to less effects of diffraction being visible).
Camera and Lens Settings
40mm f/13.0 3.8s ISO 100 2757 x 4066px