With the big US fireworks demonstrations about to begin, here's the quick and dirty technique advice:
- Camera on a tripod. Find your spot early. Consider foreground silhouette possibilities (option: light foreground with flash). Be aware of potential platform vibrations! Decks and buildings aren't necessarily fully stable, especially when you start putting lots of people on them and those big bangs start rattling things. That translates into "squigglies" in the tails of the fireworks.
- Lens that has a manual focus to infinity on camera. Note that most ED lenses focus past infinity. Use an older lens that you can reliably focus to a fixed distance (usually at infinity or near it). It's almost certain that you can't focus via the viewfinder. Live View helps some, but I prefer to use a known focus distance via the lens ring.
- Use the base ISO on your camera. Turn Auto ISO off.
- Do not use enhanced Picture Control settings (JPEG users). Use Neutral, -1 contrast. Believe me, you'll have enough contrast and color saturation. If you use enhanced settings you may just start blowing out channels.
- Set camera to manual exposure.
- Aperture should usually be between f/8 and f/16. Which aperture you use depends upon how close you are to the fireworks (smaller apertures for close work, larger apertures for far work). The aperture determines the "exposure of the burst."
- Shutter speed determines the length of the trails. Often that means Bulb or long exposures to get full sets of trails or multiple bursts. Since we're talking exposures measured in seconds here, you have a problem: hot pixels. The temptation is to turn Long Exp NR on, but this means that a four second exposure needs another four seconds to process on most of the Nikon bodies. Thus, you miss some bursts. Instead, turn Long Exp NR reduction off. At the beginning and end of the show take a couple of noise reference frames (lens cap on) at the shutter speeds you used. That way, if you have hot pixel or other noise issues in your images, you can post process that noise out.
- Use a remote instead of jabbing at the shutter release. If you're close enough to hear the mortars being fired, open the shutter just after you hear the mortar, don't wait for the fireworks to appear! You want to capture the initial burst as well as the tail, so don't wait until you see the fireworks.
- Verify all of the above by chimping your first few frames. In brightly lit urban areas you may have to deal with foreground exposures. Your choices: silhouette, lit artificially, use aperture/shutter speed adjustments to bring in foreground. Also, since some fireworks shows go off just into twilight, the foreground/sky exposure may change during the course of the show.