What you will need -
Camera - batteries charged, memory cards empty
Tripod
Remote Control (should you have one)
Torch
Warm clothes.

Camera Settings
Camera Mode - Manual (Fireworks mode if your camera
does not have Manual control)
ISO - Lowest possible (100 or 200)
Shutter - 5 or 6 seconds. I've found 5-6 seconds gives enough time for the firework to take off and explode.
Aperture - f11- f16 maybe higher
White Balance - Tungsten/Incandescent or set for any artificial light in your scene. If shooting in RAW the WB is not as important, but it's good to set a preset WB as the very bright changing colours can have an effect on the colours being accurate.
Flash - Set to off
Image Stabilisation/Vibration Reduction - Set to off
Get there early to find a location. Be aware that when the crowds arrive you may have trouble with people knocking your tripod, so find somewhere with space if possible. Make note of the wind direction, you don't want the smoke going into your face.
Including any interesting scenery such as buildings, bridges etc as they can add interest, and it is a good idea to set your exposure for the object before the start if it is floodlit to get that exposed correctly.
Try to be familiar with how to change your camera settings before the event as trying to change things in the dark can be stressful, which is why the torch can be useful.
Use the remote control setting on your camera or the Self Timer setting.
I focus on the 1st explosion, or any practise explosions, and then set the camera to manual focus so that focus is locked. Some say set the lens to infinity but I've had soft results even when the fireworks were quite a distance away. It should make no differences at this high apertures, but I'm going from my experience.
I normally leave a bit of space at the top of the frame for the higher explosions they tend to throw in, but then most of your fireworks will only cover a small part of your image, it's up to you to decide how you want to frame the explosions. If you zoom in or out, focus again, switching to auto focus, and then back to manual focus when focus is set.
Check your exposure after the first few explosions using the aperture to let more or less light in if needed. If you are under exposing set a wider Aperture (lower f number). If you are over exposing set a smaller Aperture (higher f number).
If it is a timed display and you know it is coming to an end, maybe because it is set to music, then shut the aperture down 2-3 stops (higher f number), and maybe the shutter speed lower too, (faster shutter speed) as they tend to throw everything up into the air at the end and you may end up with a big white blob as too many explosions over expose.
Good luck.
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