Sure, let's go with that. Overwhelmingly, the consensus is that the HD looks sharp due to poor eyesight of an overwhelming number of individuals.
Makes perfect sense.
James,
I'm glad you now understand the crux of the issue.:t:
Seriously though, this is something the industry needs to sort out. The ISO standard all of the big companies did allow 'high quality' binoculars to have a full objective resolution that is roughly 2 fold worse than the diffraction limit. If most of that aberration is confined to the peripery of the objective that wouldn't be much of a problem, as that is blocked by the iris of the eye in bright viewing conditions. However if the aberrations were more uniformly distributed then it means that those with 20/15 vision should be able to pick up the problem with poorer samples. You would probably need to be 20/12 or better for the worst of those samples I saw. That's less than 10% of the population. I've now tested a few £200 binoculars that would match the premium models for effective resolution and easily beat those Conquests I tried..
I did discuss the problem with one of the senior people at Zeiss a couple of years ago and he assured me they would be developing a new QC protocol, but I don't know if that would cover their binoculars made by third parties.
The ISO standard was revised earlier this year. Bizarrely for 8 and 10x42s the "high quality" limit was actually relaxed to 2.5 times worse than the diffraction limit. Expect more dodgy binoculars in the future.
David