When I was on the cruise recently I was chatting with a photographer about shooting fireworks. The next day he showed me a few of his shots from the show the night before. The pictures were awesome and full off fireworks, he had 100 ISO @ F8 and bulb mode. He kept the exposure open and kept putting a black card up to the lens and removing it when he wanted to shoot the fireworks. So he had like 4 sets of blasts in one shot, the effect was amazing. Anyone else tried this technique?