Hehe...I used to know that but it's been a looooong time since I took a photography class when I was in College. I took it as an elective Arts class AND couldn't for the life of me remember the term. I was thinking depth of focus but I knew that wasn't right.
Back in the day I could develop my own black and white photos (twisting the film in the canister for developing the negative was a nightmare to do in the dark back then, circa 1992). I loved playing with exposures in the darkroom. It's been so long since I had a chance to play with all of that. Thanks for the reminder though!

I've gotten lazy with digital cameras and photoshop. I'm sure they have digi's though where you can play with the f-stop. I will have to get one of those again someday!
Oh! and I loved playing with colored lenses back then too!