On a camera, the focal length of a lens (how close/far the lens is from the film) has something to do with the amount of light that hits the frame of film. Is that because of the inverse square law?
I found this forum on Google. This may not be the right section so excuse me if so. I have a rather simple question though.
When you take a magnifying glass on a sunny day and position it just right over a piece of paper, the paper will start to burn. Is the inverse square law (distance) the...