Hi
aiyo.....this is a mess....with all the different advice..
nek - u know why your pictures are dark? what are u doing with -1 flash exposure comp in the 2 example pics above??!!!?!?
without actually seeing the theatrette u're in, i can only conjecture a few possible scenarios. In a dimly lit room with only spotlights, there's likely to be no way to use flash without destroying the ambient too much. You can go the route of eliminating flash altogether, or use it for very mild fill, but as you have discovered, with colour emulsions / digital, you will end up with colour casts.
so first of all you need to make some technical decisions for flash use. For me (and that's me), since it is too dim for decent handholdable speeds, i would choose to let the flash be the main source of illumination. This helps to get the subject nicely lit, freeze motion, allow me a smaller aperture for more DOF, and eliminates the ugly colour cast of artificial lighting. And that means switching the camera to manual mode, choosing a moderate aperture of around f4 to f5.6 depending how much DOF i want (a group shot requires more DOF), and setting the shutter to 1/50 to 1/60. ISO will be set to 800 for a good combination of speed and grain / noise balance. The EV value for this combination of aperture and shutter speeds will still allow me to retain some ambient light, giving background with details, with the subjects well illuminated and details well brought out by the strobe. I would use a bounce card to soften the light hitting the subject.
For more dynamic / action based shots, you might want try something more experimental. You can try exposing correctly for ambient, which means a shutter speed that is not handholdable. However, throw in a hint of fill flash (or just let the flash do its normal work without compensation) and you will get subjects frozen in motion but with nice motion trails and often stylistically blurred backgrounds. The entire scene will be well lit (cos u exposed for ambient). This is now my favourite mode of flash use, but only for dynamic subjects.
Some pple call that technique slow sync flash, watever. Just don't try it for normal shots else u will get ghosting effects and many pple will question you for that. I understand some magazine / picture edtiors do not like slow sync effects.
If u're feeling really gungho, or shooting theatre / stage work, you can try shooting available light, or with the minimum of fill flash, but be aware of the colour cast issues. For stage work / dance / theatre, colour cast is good since stage lighting is often colourful and varied, but not so for such corporate events!
i did a paid shoot at Hard Rock Cafe recently in December, and i'm sure HRC is just as dark, if not darker, than the theatrette u got there. These are stuff that i applied in real life. And they work, just as in previous shoots.
