A Ring Flash, as its name implies, is a flash that is in the form of a ring. It usually slides over your camera lens. Used for macro photography, it allows the subject to be evenly lit from all directions, thus avoiding harsh shadows.
This Do-It-Yourself project actually looks easily doable even if you are a klutz with scissors and glue. It uses paper to build a ring flash. However, instead of having its own flash light, it makes use of your external speedlite mounted on your DSLR, redirecting the light down to the paper ring around the lens. The article is well illustrated.
Read the article at: DIY Photography.
