Flash in the Pan

I've just recently started using off camera flash (see yesterdays blip). I thought a blip about the setup might be of interest to some.

Most of my indoor shots use flash. I use the 580EX Speedlite. It's expensive but it's so good. It has a swivel head so that you can bounce the light off walls and ceilings. I rarely point the flash directly at the subject. About the only times I do is if there are no surfaces to bounce off, or there is bright sunlight and I need to fill in the shadows.

I use the flash in E-TTL II mode. This mode makes using flash very easy. You simply tell the camera "how much" light from the flash you want in your picture using a setting called Flash Exposure Compensation (FEC). So I point my flash in the direction of where I want to bounce it, set the FEC level I want, then shoot. Really easy.

So how does the camera know how much flash power to use? Simple, it does a test. When you press the shutter button the camera tells the flash fire a small amount of light and then measures the resulting brightness of this small "pre-flash" on the scene using the normal Through-The-Lens (TTL) metering that it normally uses to calculate exposure. From the test exposure it then figures out how bright the real flash has to be in order to match the FEC level you set and fires the flash accordingly. It does this all extremely fast. You don't notice the pre-flash or any delay in taking the image.

The setup I have shown in the blip is pretty much the same thing but two flashes are used. One of the great features of the 580EX is that it can remotely control other Speedlites that support slave mode. In my case the second flash is a 430EX. I use the flash on the camera to bounce light off the ceiling and provide a fill light. I used the other flash with the umbrella to create a main light. The umbrella is just a way to make the flash light bigger and so creates softer shadows.

Again the beauty here is that I simply set the FEC level for each of Speedlites (from the camera no less) and the camera works it all out using pre-flashes.

Probably way too much information but I do know that some blippers have recently gotten nice new 580EXs so they might be interested in some of this. Nikon Speedlites also have these features, as probably do most brands of flashes.

Planet Neil : Flash Techniques[/url] - mainly about on-camera flash
Strobist : Lighting-101 - about off-camera flash]