A ring flash is a gadget that has multiple flash units that wrap around the lens instead of sitting atop your camera and generating a single source of light. They all fire together, generating a ring of light that illuminates your subject from every direction. Serious photographers--with deep pockets--sometimes purchase sophisticated ring flashes for their digital SLRs. Canon photographers, for example, might choose a $500 Macro Ring Lite for close-up photography.

Of course, $500 (or more) is a lot of money to spend on a flash that you'll use only occasionally. You can make your own inexpensive ring flash for about $10 worth of household goods--a couple of plastic bowls, glue, tape, and foil. Or you can buy an inexpensive one. Photojojo's Ring Flash Adapter, for example, costs just $40.

You might think of your flash just as a replacement for the sun, and therefore you only use it at night or in other dark situations. But the flash is much more than that: You can use it to fill in shadows that would normally occur when shooting outdoors in bright sunlight. To do that, just set your camera's flash to its "Fill" or "Forced Flash" mode, in which it fires all the time, even if there's otherwise sufficient light available. This way, you can fill in shadows and even the contrast in your portrait photos, or, if you're shooting towards the sun, you can prevent your subject from turning into a silhouette, as in this example.