Occasionally I like to review what I think I know about an area of the photography. It's lead to new insights and challenged a few long held beliefs. With this in mind, I find it interesting that there is often some uncertainty among photographers regarding the fundamental question of what the exposure meter reads and its connection to film exposure. The discussion usually centers broadly around percentages, Zones, or other nonspecific terms, but does this really explain it? This is a subject that Ive covered before, although its never been the topic of a thread.