Quote Originally Posted by berrywise
I always thought is was kinda messed up how when you stop down you actually go up to larger "numbered" f-stop.
Simple! The f/stop number is the ratio of the lens focal length to the diameter of the aperture. Optics defined this and the definition pre-dated cameras. This means that the diameter of the aperture is an inverse proportion (the aperture diameter is on the bottom). As the bottom gets large, the entire fraction gets smaller.