I have been doing party photography for a short while now, and I have a special theme party coming up next week. it will be a backlight party with luminous paint and everything. My standard party photography setup is: Canon 400d / Sigma 10-20 f4-5.6 / Canon Speedlight 430ex The speedlight is a problem now, since a flash would ruin the backlight effect. By searching the internet on tips for shooting a backlight party, I only found one page, which suggested shooting at a very high iso, as the shutter speed must stay low. He shot at 2400, while now after an upgrade he would be able to get even higher. My camera only goes to 1600, and I am afraid the pictures will become too noisy. Or will noise not be such a big problem seen the fact the pictures will already have shifted colors? I guess I will have to use my lens full open, or should i even consider taking my kit lens for the .5 aperture advantage against the disadvantage of a longer focal length?