Re: 80/90 headlights, what do you think?

[enzeder@ix.netcom.com]

On 10/04/97 10:29:24 you wrote:
>
>In message <199710040904.JAA225936@out2.ibm.net> "Bruce Bell" writes:
>
>> Yes, that is what I meant. :-)  I was thinking of the inverse distance
>> squared relationship and I should know by now not to take verbal shortcuts
>> on this list. Gee, If I'd just used the word "perceived" or
>> "effective".........
>
>The absolute luminosity of an object is independent of its distance from
>the observer.
>
>True - the inverse square law results in only a quarter as much light
>reaching you if it's twice as far away - but the area of the image on
>your retina is also only a quarter of the size, and it cancels out.
>
>Light per unit area of image remains the same.  The greatest loss is
>in visual contrast because air is not completely transparent and
>reflects a lot of stray light back to the observer.


Maybe I'm wrong about this, but isn't that inverse square law related to the 
fact that light is given off in all directions so the amount of light falling 
on one square foot that is a meter from the light source will be 4 times that 
than at 2 meters?  Won't the fact that a headlight will reflect "most" of the 
light in one direction make the relationship more linear than exponential?  
Maybe not 1/2x, but certainly better that 1/x^2.

While you're here, do you know where I can get a close-up look at a Euro spec 
headlight for a '86 5kcst?  Either on the web or perhaps sent directly to me.  
I'm curious to know what they actually look like.

Arryn.