Advice on night/fire performance shots

Hello all!

I just finished reading "Ben's Newbie Guide to Digital SLR Photography" and, while I learned a great deal, I was wondering if I could get a little situation-specific advice. I'm shooting a group of people who do fire hooping, eating, poi, etc choreographed to music. Basically a lot of fast movements at night with fire and I'm having difficulty "capturing the moment" so to speak. I'm looking for a good starting point for settings that will capture some of the fire while keeping the subject as crisp as possible. A friend suggested a delayed flash w/ a canon 50mm 1.8ef lens. Anyway... here's what I'm using as well as a few shots w/ the settings I used: 20D, 420ex flash, 28-135mm Ultrasonic.
1st pic: fstop 5.6, iso 1600, shutter 1/125
2nd pic: fstop 3.5, iso 400, shutter 1/20

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This year I have shot firedancers a couple times. Last time was sunday.

I will follow this thread as I also need some advice on how to capture the fire exposed properly. I have not used flash most of the time because the photos I have taken so far with flash did not turn out to my liking.

tommykjensen wrote in post #8960513
I have not used flash most of the time because the photos I have taken so far with flash did not turn out to my liking.

I'm probably just not doing it right, but I don't really like using the flash either.
Judging by some of your fire poi shots, hope you don't mind I checked out your site in your sig, I need to try other iso's than just 1600. For this past weekends shoot, my decision to just leave it on 1600 and hope for the best was not a wise one... lots of very grainy shots Unfortunately i only shot in jpeg as well. Ah well... live and learn. I'm lucky enough to be dating one of the fire dancers so I'm sure I'll get more opportunities

By the way I liked your fire shots. The location was well chosen.

Don't mind you checking my site at all, after all that why the link is there

The grains I think you just have to accept because you need shutter times that will result in minimum motion blur on the performers but at the same time give alot of motion blur on the fire for the nice patterns.

I suggest that you meter for the fire & use the flash on "M" with a warm gel to help light the people. Some flashes will do that on auto, but I don't have one & so someone else will have to say what their experience is.
I use old Vivitar flashes that have a continuously variable manual mode with a Varipower module in post #3.
Simple "every-day-emergency" location lighting

For calculating a M exposure with strobe, this might help understand how distance relates to flash output:
Fill light at sunset