Thanks heaps Benji, just to clear something up, is a ring flash is used off camera or on camera?
There are three types. An on camera type like dentists use. These are quite small (about six inches in diameter) and are mainly used for macro work where the item to be photographed is a few inches away from the lens.
Then there are somewhat larger units like the ABR800 sold by AlienBee. This unit is about 14 inches in diameter and has a handle to hold both it and the camera at the same time. It is a little cumbersome, but could also be considered "on camera" although it can be mounted to a tripod.
The last type are the DIY units. The sizes of these vary by the whim of the maker. I made one that is about 52 inches in diameter, with a 32 inch hole in the middle. I can still shoot from 6 to 10 feet away from my subject with my mid-telephoto lens and not get the unit in the image.
Benji

