No matter what kind of subjects or photography we’re speaking of, great pictures begin with great composition — that is, the placement and arrangement of subjects in the image.
Fireworks pictures are no different, but they present a challenge since you can’t see your final subject until it explodes in the night sky and you’re actually capturing it.
You don’t always want to be among the spectators closest to the fireworks themselves. By backing off and occasionally using a telephoto lens, it’s sometimes easier to get good, sharp images of a burst of fireworks, compared to looking upward with a wider-angle lens.
Look at the first burst or two to judge how much of the sky they take up, how high they go and what lens(es) will be appropriate for the types of shots you’re looking for. Remember, you can back-off with a wide-angle lens and incorporate more of the surrounding area (possibly a powerful technique near a city skyline) or you can zoom in with more of a telephoto lens to emphasize the colors from the fireworks themselves with less emphasis on the surrounding sky.
Just as when you’re shooting pictures of people, consider whether to use horizontal or vertical composition. Try to look through the viewfinder during the first burst or two to judge what will most effectively fill the frame and the amount of background information you want. Also, don’t let your eyes play tricks on you when you look through your viewfinder or use the Live View feature on your camera: it’s easy to concentrate visually on the fireworks’ burst as it happens and lose sight of the fact that there may be large black areas of surrounding sky that you’re not taking into account. Always try to judge the position and size of the subject in the context of the entire picture area, from corner to corner. The Live View feature of many recent EOS models can be useful to get an idea from the first burst or two of how the frame will be filled.
Try mixing things up as you shoot the show. Change lens apertures, alter the number of bursts you capture on a single frame, vary your zoom setting, shoot some pictures with foreground details and others where you’re zoomed in more on the sky. The more you shoot, the better the chances of some really exciting pictures.