Well, one of us is correct and the other one isn't.
Your comment: [color=rgb(40,40,40);font-family:'Merriweather Sans', sans-serif;background-color:rgb(242,242,242);]The throw distance, has no bearing on the brightness of the image[/color]
Is not correct.
While the TD itself will not cause a direct difference in light output, how the internal optics of the lense deal with the throw distance (to maintain the same screen size) will cause a difference in light output.
I guess if you are wanting to have a purely semantical argument on throw distance, then you would be correct, but not correct if you want to factor in how the lense deals with the increased mechanical zooming of the optics.
Perhaps I was mis reading what you were trying say? Not sure, Im currently on pain killers :-)
Thanks for the response Gregge..it's nice when one can have an intelligent discussion about a subject. So you are saying it is the optics that are changing the brightness, not the TD!...that sort of proves my point. I would still say....using the same lense, keeping the image the same size, and moving the projector further away, does not diminish the brightness of the image. Try it sometime...you'll see.