If you have ever wanted to switch the little dial on your SLR camera from automatic to manual, you may have been confronted by the array of numbers and choices and how they hell they all relate. Even after years of photography, I still think the relation between aperture size, f-stop and depth of field seems totally Irish.
This is the sweetest cheat sheet I've seen that lays out the facts clearly and with style. Developed by a very talented photographer called Miquel Yatco and originally posted on his blog, Living in the Stills.
So flick the switch and have some fun with shutter speed, ISO and depth of field. Trust me, the camera will not explode, and with digital, you won't even be "wasting" precious film.