F-Stop

http://www.picturecorrect.com/tips/aperture-and-shutter-science-of-the-f-stop/

In this article it explained how to use F-stop and what Aperture was. The article was saying that if the F-stop number was larger then the less light went in. It as well stated that if the F-stop was smaller then more light would be able to be let in. Then it started talking about how to do special effects.