Quotes: "The sharpness data on photodo for example suggest that every Nikkor lens that I found that had MTF data except 1, (500 mm) was better/sharper at smaller apertures as optical physics sort of suggests." & "The lenses I refered to would be the 300 f 2.8, 400 f 2.8, 500 f 4, and 600 f 4"
These long fast lenses are designed to be used wide-open. Or at least they are used wide-open for the vast majority of shots - they probably do get better stopped down, but this isn't to say that they are not good at full aperture where they are most used.
Shorter focal lengths are generally designed with the idea being that they WILL be used stopped down and this is where they usually optimise (f/8~11). This is true of most short focal length lenses which generall optimise at 2~3 stops below maximum (although I suspect many zooms optimise at 3~4 stops below maximum. Very fast short lenses will generally operate very well at their widest aperture (why else would you want them but to use wide-open?), but they too will optimise at 2~3 stops below maximum.
All this said, all but the cheapest of lenses will usually produce pretty decent images - I've never lost an image sale due to an optical consideration (mind you I wouldn't use very cheap lenses!). I used to test lenses (and produce the MTF data on them). Todays optics are pretty reasonable on the whole!!!
