Like I wrote, I'm not the person for doing lens comparison testing. However, today the Wife & I were out and about running errands ready for our trip, and we drove past this. I thought I'd previously shot it with the 14-28mm, as it turned out I had used the Lumix 20-60mm. Which is no slouch. Pretty damn sharp stopped down to my eye to be honest. Anyway, to the annoyance of the Wife, I stopped and shot a couple of frames. Yeah yeah yeah, I know, it's a totally flawed test if you want scientifically controlled etc. Different day, different light, slightly different focal length and I moved a bit to try and match the framing -from memory, and so on. But it is what it is, real world shooting. See what you think. If you click on them it'll take you to Flickr and they're viewable at full resolution there. That's as far as I'm going to go with tests.
View attachment 9791250125-P1025032 by
Markus Welder, on Flickr
View attachment 9792250323-P1025937 by
Markus Welder, on Flickr
I did do a couple of really really boring shots the other day with the 14-28mm & 18mm both at F4.5, I can't pick any difference. Any difference there might be is just due to slightly different focus points, to me they're indistinguishable. But the 18mm opens right up to 1.8, the 14-28mm is stuck at F4.5 at that focal length. I think. They're all good. No, make that excellent.