I was messing around on Wikipedia and came across the Depth of Field entry. There's a diagram in there that really helped me to understand exactly how aperture works inside a camera. Just thought I'd share it.. hopefully it helps others understand. I always knew what it did, to a point, but never understood how it worked. Source: http://en.wikipedia.org/wiki/Depth_of_field EDIT: Oops, made a typo in the thread title. Ignore that.