Corona? Penumbra? Spill Beam? ???

Some Questions:

Being a relatively new "flashaholic", I am curious about the terms used to describe the beam characteristics. I have often used the term "Corona" to describe the ring of light that surrounds the hotspot, and "spill beam" to describe the large ring of dimmer light that extends out beyond the Corona.

Others differ - I noticed that at LEDMUSEUM.org he uses the term "penumbra" to describe the area around the hotspot, and "corona" to describe the "spill beam".

When I look up these terms the definitions are more geared towards describing the characteristics of the Sun, and in my opinion are not definitive enough to say with any conviction which term actually applies to which portion of a flashlight beam shining on a wall.

Is there a definitive answer somewhere? What is the correct term for the ring of light that immediately surrounds the hotpsot? Corona or Penumbra?

How about the spill beam? Is it proplerly called a "Corona" or just "Spill Beam", or something else?

I didn't see this in the FAQ.

There is no "official" or definite answer, but around here we use the following terms ...
- hot spot
- corona = spill beam
... and we do understand each other relatively well .

The term penumbra reminds me too much of a medical term as it is used to describe the tissue surrounding a stroke area being in danger of dying, too. The term isn't used much if at all to describe beams here on CPF.

If you want to describe a beam it is also useful to say something about the transition from hotspot to corona, and together with the description of the spot and the corona you are all set.

bernie