I recently shoot fireworks on new year's day and I was pretty satisfied with results I got. I must admit this was my first attempt of fireworks shot and I had given lot about it before clicking. I simply studied EXIF data of thousands of fireworks pictures on internet and tried to create a rationale for perfect firwork shot. My observation was that choosing very narrow aperture will help to keep shot as clean as possible. This is because, when firework bursts in the air, produces significant amount of light and can easily help in overexposing shot. So if you click with very narrow aperture (i used f/16) you will allow very less light entering into the lens. Although it no hard and fast rule that you must use narrow aperture only. About shutter speed, if you are going to use timed shutter, then you will have to be very lucky to catch perfect one firework shot. As in timed shot, you have chances of mixing more than fireworks in same shot which may not look good always. I used BULB (as many does) mode and it worked perfectly for fireworks shot. Its like almost designed for this shot. In this mode, you use remote control to release shutter and press remote again to close shutter. So the trick is, you press remote button when you see firework starts going up in air, and then press remote button again as soon as firework explodes completely. If you leave shutter open for longer, you may catch another interefering firework or even smoke from firework that just finished exploding. So you need to be very quick to close shutter. About focus, it is quite understandable that before show starts, you have no idea at what height exactly the firework is going to explode. There are 2 options. 1 - Manual focus is must and focus to infinity. You can do this by trying focus longest object you can see at ground level. For example a bldg which is at far distance. Option 2 - (I prefer this) Set your camera with tripod, aperture, desired view frame and just wait for 1st firework to explode. Once it starts, they come back to back pretty quickly and you can quickly set manual focus on initial few fireworks and then use that focus. I used this technique and it worked perfectly for me. Another important thing is wind causing shake to your tripod and cam. If its going to be windy when you will take photos, make sure attach a rope at the center of tripod and attach some tesion of around 6-8 pounds. This gives stability to tripod and resistance against wind. Once you are off taking shots, quickly check few shots initially and then dont go back to screen preview until show ends. If you have done above exercise good enough, you will have decent results.
These are some of the shots I took on 1st Jan at Baltimore Harbor.
Complete set seen here -
http://flickr.com/photos/abhijittembhek ... 120653482/