If you are using a 56mm or 62mm light ring, follow these steps to obtain a brighter, clearer image. This technique works with 100mm light rings, too (just cut the hole larger).
Take a small cardboard box and cut out a 2 1/2" (64mm) diameter hole in one side. Then spray paint the inside of the box flat black. Fold in the flaps and tape them closed. You can paint the outside if you like:
Remove the bottom cover from the light ring. Set the light ring over the hole (once the paint has dried :>) and place a magnet on top of the cell. Even in a bright environment, the flux is clearly revealed:
And much brighter and more defined with the room darkened: