A ring flash can be a great addition to any macro lens. When you think about how much less light there is hitting a single bug than there is hitting a whole mountain scene, you start to see why macro photography needs so much more light to get sharp shots. The mountains don't move, but that bee in flight can be nothing but a blur without a flash. Traditional flashes are too far away and aren't designed for extreme closeups.
There are quite a few options out there, or you cam make one yourself. The one pictured above is one of the most ingenious camera hacks I've ever seen, though it has some competition from that guy who figured out how to use a rooster as a steadycam. Rather than using LEDs or other lights that need batteries and have to be synchronized with the camera, this one uses fiber optic cables to transmit light from the flash on your camera, taking advantage of the fact that the flash is already synchronized with the camera and puts out an impressive amount of light. No extra power cords or batteries necessary, and the ring setup with 150 fiber optic cables distributes the ...