I've seen on Flickr that the photographers specify values for four settings about their photos (where exif data is available) -
- Shutter speed
- F number
- Focal Length
An example can be found here.
I would like to know the aperture size (diameter), but they don't specify it. Knowing that the F/number is the ratio of the focal length on the aperture, why is it so important?
It appears that F/number is less precise than having both aperture and focal length (because it's impossible to know about the aperture and focal length if only F/number is provided). Plus, as it is a ratio, it's more complicated to understand than the two numbers it's based on.
So which information is more relevant, and why?