Good points Dominique,
I think we tend to process for our normal output medium, and mine is print. So many of my jpegs will appear over-sharpened at 100% screen resolution. The sparklies are one characteristic for sure. I think my issue with the train shot was I applied my normal workflow to the raws, and that 40HR is so freaking sharp that it ends up over-done for 100% web, and probably for print too. Chalk it up to learning curve with a piece of equipment I had access to for 48 hours only. On the other hand, the train car was freshly waxed and those rivets are lit by direct sun, as are the waxy leaves on the bush in the background, so at least some of those are likely to be true speculars...
Back to the 80LS.
Edge sharpness is very good wide open, but it is not anything close to what the center is. I'll try and post a comparable crop from that above frame if there is something near the corners near the focus plane. If not, I'll find another f2.8 and post the corners. The extreme corners go soft on my P65+ at f2.8.
Honestly, I think it's already resolving better than the sensor at the center wide open, so stopping down doesn't add much there other than DoF. However, contrast pops up a little and that can add the appearance of being sharper. Again, I can try to post some crops if I can find some that are relevant.