Josh Stromberg has performed some actual real-world lens + sharpening tests in an article called "Lens Sharpness in the Digital World." I've been thinking about a replacement camera lately, which of course for me means thinking about lenses. I know a fair amount about lenses from an enthusiast standpoint, although not very much from a scientific one.
What knowledge I do have is 80% empirical: try it, look at the results, decide what I think. It's not the most rigorous knowledge. Phil Davis used to refer to me as an "eyeballer," not always meaning it as a compliment. But at least it's practical....
READ ON (Warning: long article)