DFA 100 for shooting butterflies.
For fireworks, a medium wide to normal lens
with a tripod You don't really need "fast"-- and depth of field shouldn't be an issue at those distances, but you'll want to shoot them with relatively long exposures. I like ~2 seconds, which means a tripod.
This was shot with a 35mm macro at f/4.5 and iso 400, 2 seconds. Nothing magical about those settings-- I wanted ISO at 400 in case I wanted to take non-fireworks pics, and the 35 needed to be stopped down to make those settings. Could have easily been ISO 150ish at f/2.8, if I did my math right. I would have, in hindsight, preferred a wider angle lens.
Fisheyes are ... unique. And if you are buying one with the thoughts of defishing the image, you're probably better off just getting a wide angle lens such as the 12-24 you mentioned.
Last edited by Mister Horrible; 06-26-2012 at 06:52 AM.