Question about shooting with flash...

[chinabuddie]

Tomorrow I am going to a Pet Expo that is held indoors at a convention center.. I'm pretty sure there will be enough lighting that I won't need to use a flash.. however I just got my 430ex and had a couple questions.

how do i know what shutter to use when i'm using a flash? i mean without the flash it's easy because the meter lets me know what exposure i'm at.. but with a flash that's on auto mode.. how do iknow whether to use like 1/200 or 1/80?

also the convention center i'm assuming has a very tall ceiling.. would it be best to bounce the light off the ceiling?

sorry i'm new to the whole FLASH thing.. i read part of the flash FAQ and stuff.. but still am kind of puzzled. Thanks

[Titus213]

When I shoot flash now I use manual mode on the camera and ETTL on the flash. That lets me meter the scene for ambient light. As long as I can hold the shutter speed and it doesn't exceed your max sync speed the flash will adjust (assuming it can get enough light on the subject). And with real high ceilings you will not be able to bounce off them. You might try simple 3x5 card banded to the flash for some reflection.

[SkipD]

If the expo is using flourescent lighting or any other lighting type that is using a gas discharge technology, I would choose to use 1/120, 1/60, or 1/30 second shutter speeds to avoid the variations in light intensity and color that you might see with other (especially faster) shutter speeds. These three shutter speeds are exact multiples of one half wave at the 60Hz line frequency.

If there's a probability that the lighting is potentially funky like flourescent lighting, I wouldn't suggest trying any other shutter speeds except to experiment and see how bad the lighting could be.

[chinabuddie]

thanks for the information everyone. do you think i would need a flash in an expo center? if i remember.. they are usually pretty well lit up.. but if i do need flash.. should i bounce it off the high ceiling.. or do direct flash? any thoughts?Thanks again

[Titus213]

It will depend on the type of lights they use in the center. As mentioned, some lights are tough to white balance. It appears OK to the eye but the camera will see something entirely different. Flash can overcome that lighting color. As Skip mentioned, if it's flourescent you have to watch your shutter speeds because of the cycle time of the flourescent lights. And mixed light can be a real issue for color balance.

Direct flash will give harsh shadows. Sometimes you can get away with it, sometimes not. I would use my bracket and Lumiquest ProMax unit. I doubt you will be able to bounce anything off the ceilings because of their height.