Atmosphere wise it think it was a tad hazy that day and I did try several apertures ranging from the minimum of the minimum but still resulting in similar quality. Though I don't think mine was causes by vibrations from wind and traffic because my place is in a rather undisturbed area of the neighbourhood and it was taken from my room which is more or less shielded from the wind. I still completely agree with you on that. i practice turning IS off on tripods too and the 50mm has no Is to speak of anyway and if I'm not wrong the shutter speed it was taken at should be high enough to prevent even hand shakes from me.
On the topic of the high megapixels I find having all 18 quite unnecessary too. Creates amazingly large file sizes even though I won't be printing or viewing it on huge cinema screens. So I reduced it to a 10mp raw and the file size dropped comfortably

or I would have been filling up my sd card way too quickly! I can't comment much on the technical aspects though, I'm not an expert and I'll just leave the debate to the experts on the correct reasoning but now I'm still undecided lol
Outch! Wall of text

Thanks again for your help

appreciate it very much!
Guess all I have to do is check the focus more thoroughly in the future