Your flash will not light up the entire auditorium, no matter how much you want it to; it just isn’t going to have enough power and no amount of flash will do it. There are times of course when it’s just not appropriate to use flash. There are also times when you just don’t want to use flash; flash would ruin everything.
But, using flash is a lot more than just popping it up and letting it do its thing. Simply popping up the pop-up flash on your DSLR or your compact camera is not the salvation to your lighting issues. Sometimes it just makes things worse. It will not light up the room and often you’ll end up with disappointing underexposed photographs.
Additionally, if your subject is staring right down the barrel, you’ll get the dreaded red-eye. But, your flash is a powerful tool for great image making.
Today’s flash guns make the whole thing very easy. A dedicated flash system like the Nikon or the Cannon system means that the flash and the camera talk to each other in terms of exposure. The camera tells the flash when it’s had enough.
And if you buy a flash with a bounce and swivel head, you can make the lighting more creative and natural. Simply tilting the flash so that it bounces off a wall or ceiling will make it look more natural. Bounce flash is very effective for that.
But what about exposure? Well, as we’ve said, exposure is often taken care of by the camera’s metering system. These days, the way that cameras and flashes communicate with one another, you can simply set your flash and camera to TTL and everything is taken care of.
This is ideal in a situation where you want to use fill flash outdoors. Fill flash is used outdoors to get rid of harsh shadows, balance out the contrast, and is used by professionals in wedding portrait photography all the time.
In fact, fill flash can be used to just compensate for those times when your film or your camera sensor can’t see everything. The idea behind the exposure is simple math.
The guide number / distance = f-stop
For example, if the guide number of your flash is 40 in metres and your subject is 10 meters, you’ll use an f-stop of f4.
But what about shutter speed? If your camera syncs up to 1/250th of a second, you can use it very effective to freeze motion. But what if you select a shutter speed that is slower and matches the available light? Well, you can use that very effectively to create the idea of both blur and frozen motion in the same photograph. Matching flash with ambient exposure is very powerful.