Originally posted by Digitalis
from an optical quality point of view the 55mm f/4 is as good as it gets. From experience and what I have seen in the work of others the Pentax 67 55mm f/4 matches and in certain areas of IQ, exceeds the Zeiss equivalent.
I can certainly say that I have experienced that with the 67 version of that 55mm I have.
Some general observations I've experienced using both the 45mm and 55mm is that the 45mm does well in shots like
bensonga shows here. That is, when you are right up close. The wide field brings it in. Or in capturing the wide grandeur of say a landscape. But when you're not right up close, the shrinking size of intermediate and distant objects lose their clarity were the 55mm will hold on to it longer. So sometimes it can be too wide.
Another issue that comes up for me on is that 82mm filter size on the 45mm. It is really inconvenient when looking for a screw-on 9 or 10 stop ND filter and a grad ND filter. And, depending on the lens combos I'm carrying, it means carrying a 3rd set of color filters for BW.
Having both those lenses and only wanting to carry along one can be a really hard decision to make too. So only having one of them can really simplify that problem.
I think these are one of the last posted shots I've done with the 55mm last year.
67 55mm, f16, 320TXP
100 Acros, f16, NDX400 filter