Re: Advice, please

Jeffrey E. Salzberg (
Wed, 21 Oct 1998 05:49:15 -0400

> 5) Brightness of your projected image has a lot to do with how big the
> final image is, and not much to do with distance. A smaller image from 100'
> away is brighter than a larger image from 30' away.

istance, however, (along with lens focal length) affects image size.

Actually, distance *does* affect intansity. The Inverse Square Law
says that intensity decrease is inversely proportional to the square
of the increase in throw. In other words, if you double the distance
from the projector to the target, you'll have 1/4 the intensity.

Jeffrey E. Salzberg, Technical Director
The Dance Conservatory
Purchase College