What is a ring flash?

[tremer]

I noticed people talking about a ring flash here:
http://focusfaction.com/forums/showthread.php/1916-Jump

What exactly is it? and whats the benefit of it?

[Adaptive]

Thread moved as per request.

This is what a ring light looks like


again

This is what a camera looks like attached to the Alienbees Ring Light









Here is a good write up from Adorama called "Lord of the Rings"
http://www.adorama.com/alc/article/8242

Here are some highlights if you don't want to read the whole article.
- The ring light’s defining feature is its circular, or doughnut-shaped flash tube and reflector.
- Ironically, the ring light violates the general rule of lighting placement.
Instead of being held away from the lens in order to produce better modeling, the ring light's axial position is intended to produce no noticeable shadows and, therefore, little modeling.
Actually there will be a halo-like shadow around the subjects, but the shadow will be very faint due to the much greater intensity of the direct light.
- Studio ring lights are the largest ring lights & can handle from 400 to 2400 watt-seconds of power.
Generally, they are AC-powered, but can be powered on location with portable generator.
The reflectors are as large as 16 inches in diameter. They can be mounted either on the camera or on a light stand directly in front of the camera so the lens looks through the ring light.

Using flash only (left) using ringlight (right)






These are some examples of photos taken with ring light where you can hardly tell ring light was used.




amateurish
Look at the (halo) shadow all around the people...
back in the day this look was seen a lot because people didn't know how to use it and it's still used intentionally sometimes (god knows why).

[wideopen]

Nice visual explanation!

[foto-graphy]

Good write up and samples.
Here are a couple photos I shot using ringlight.