It surprises me that so many people seem to feel that the concept of f-stops is so intellectually challenging. Shotgun users easily understand that 20-gauge shells are smaller than 12-gauge, electricians easily understand that 18-gauge wire is much smaller than 14-gauge. It's not that difficult.
More importantly, it's based on a simple mathematical relationship: focal length divided by lens opening. This makes the numbers applicable to any focal length lens, and makes exposure easy to determine. These are reality-based numbers. They do require an understanding of fifth-grade (or so) simple division. Since they indirectly indicate the amount of area that light can pass through (which is what matters for exposure), they're stepped in halves and doubles, e.g.. 2.8, 4, 5.6, just like shutter speeds are stepped in halves and doubles. This isn't rocket science, it isn't even algebra. To switch to an arbitrary system of numbers with no physical basis would make it simpler on the first day you picked up a camera, but you'd never progress any further in your understanding of light levels and camera settings. "Set your camera at lens opening 2 and 1/60 or lens opening 4 at 1/15"? 2 whats, 4 whats? Piano keys aren't numbered, from left, 1,2,3,4,5,6, and, if you saw a keyboard like that, you'd assume a user of such a piano wasn't too bright. Pianos have 88 keys, but there are only 9 full f-stops from f1.4 to f22, and they're in logical steps. If a normal person can easily remember several 10-digit phone numbers, the basic f-stop scale should be easy, especially since it's been around for nearly a century (correct me if I'm wrong about that). So there's my opinion. Pat White
