[Radiance-general] Questions about spotlight and specularity

[Joe]

Hello,
I am new to Radiance, have some questions and hope
that you can help me.

Here is an image to illustrate my questions:
http://imgur.com/M2ln4Sb

About spotlights.

1.)

Does each point of e.g. a ring act as single spotlight when spotlight
is assigned to a surface? (upper left image)

2.)

When I assign a spotlight to a ring, how does the direction of the 
ring's normal
and the direction of the spotlight act together?

I would have expected the light spot to get elliptic when the spotlight 
is pointing
downwards but the ring has a different normal. (like the projected
area of the ring when looking in the direction of the light)
But the light spot stays round. Why?

3.)

I found a comment in Radiance Digest

> The focal length produces only a subtle difference as it shifts the 
> effective
> position of the source behind the actual emitting surface.

I interpret this as shown in the lower image. Is this correct?

4.) Is the "specularity" parameter for the materials the same as 
"reflectivity" or "reflectance"?

Kind regards,
Joe