Jim Peters wrote:
Just Bracket Your Head Off! After All You Wont Be Paying For Film Today! So Enjoy!
In my humble opinion, one of the best suggestions.
What I'm reading in your original post is that you aren't wanting to be the main photographer, you just want some good shots of your own.
I don't know the arrangements with the "main" photographer, but you should find out in advance. Some will pack up and go home if others start jumping in and taking photos. Think what all those other flashes will do to his/her set up. I've had MANY shots that would have been wonderful, only to be blown out because someone else jumped in front of me and took a shot at the same time. The other thing is, I sometimes use off camera flash, and before going to radio triggers, other people's flashes would set off my flash, ruin their shots, and sometimes mine because the flash was recycling when I pressed the button.
IF (that's right a BIG if) the main photographer is fine with you shooting, then if you aren't used to shooting in this type of light, set your camera up in "night portrait" mode if it has one, and also bracket, bracket, bracket.
If you bracket your photos, at least 1 of every three should come out like you want :-)
I'm not familiar with your camera, but from posts above, I see that someone suggested bouncing the flash. Not possible outside.
If you don't normally shoot in manual mode. A wedding is NOT the time to start practicing. Shooting at home is the best time to do that. Go out at the same time of the evening at your house, set up some lights, and candles, and shoot away. If you do that, and get satisfactory results, then by all means, shoot manual.
I know several wedding photographers, that shoot in aperture mode or sometimes program mode. The key is to get good exposure. Good luck with whatever you do. We'd like to see some of your photos.