Yes my friend, photo flash can be a cruel mistress.… well, let’s just say it’s easy for even the working pro to get unpredictable results. So here are some tips I gave a young associate on handling flash in situations like an auditorium where the subject might have a fair amount of stage light hit them, but not enough to go without flash. The same holds true with bright florescent lighting.
Normally I suggest when a subject is in a normal tungsten environment, you shoot flash for the subject exposure and drag the shutter (lower the shutter speed to like 1/15th) for the background to not be a dark cave. BUT when the person is in pretty strong spot lights, up the shutter speed and the aperture (Use manual F4 125th say, or Program mode maybe, or Shutter Priority but 125th or 250th of a second). I bounce around through all of those choices till I find what works in a particular situation.
You’ll find shots much crisper with just a little change (eg F4 and a 60th) than at 2.8 at 1/25th.
Remember when there are lots of dark suits, and those dark blue gowns, and maybe a dark room, your flash will tend to overexpose as it reads the whole scene and thinks it’s a good even exposure (something it made glow and something black = a nice middle gray good exposure to your camera!)
Same with white gowns, white dress shirts, white walls… they all make the camera muddy the exposure, so up your exposure a bit.
To do that, learn about your +/- buttons. There’s one for just the Flash, and one for the overall exposure, and they affect each other in magical, confusing ways.
Reset at the End of the Shoot:
AND remember at the end of any shoot to check your ISO, color tweaks, +/- and reset it all to zero so you don’t mess up your first shots on your next shoot.
To get really good with using flash, check out books and DVDs from the PhotoVision people HERE or this book by Joe McNally is amazing: