Following up from this question I would like to know what could be the correct metering mode that I should use to shoot fireworks? Since evaluative mode could be tricked here since the a large area of the scene will be dark. It looks like this situation is similar to shooting the moon.
No metering mode applies here. If you are shooting Bulb, the camera has no idea how long you will keep the shutter open, so it simply does not meter. You can also do it in manual (M) mode in which case the meter operates (to show you the offset from ideal exposure) but does not matter either. These fireworks shots were all done in Manual mode.
Metering rarely works since you have a very dark scene when you begin shooting, then when the firework explodes it emits very bright light which would cause the whole thing to seriously blow out. This applies for shooting the fireworks along.
The other possibility is to shoot a scene, in which case you have to found a good overall exposure for the scene, either in Manual mode or a semi-automatic mode with multi-segment metering (usually). Then you shift the exposure to get the shutter-speed you want for the firework. It's a lot of trial-and-error since fireworks vary so much in timing and intensity.
I was shooting fireworks a few weeks ago, and I used manual, because setting the speed and aperture have quite different effects in this case. (I.e. the automatic setting, which assumes that both control the brightness/exposure of the final result, simply does not work.)
Fireworks are essentially moving particles of light. The speed (exposure time) you use will not influence the brightness of the streaks on the image---it is the movement speed of the particles that determines how long a given sensor pixel will be exposed to their light. The speed setting of your camera will only determine the length of the light streaks. (Of course if you use a very long exposure, the smoke in the background will be more visible.)
To control the brightness (exposure), you can use the aperture setting.
I did a few experiments to find out what aperture will give the correct exposure, and then played with the speed to get different effects. I needed to adjust the aperture a bit sometimes for different types of fireworks, but you'll quickly get a feel for this after a few test shots.