I just got to this thread, a couple weeks late, referred from:
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/55093-have-som...a-12-24-a.html I have the 10-17, and a couple other lesser fisheyes; and the 12-24 may be next on my LBA list. All these shots are interesting and show that these are
very different lenses, at least at their extremes. IMHO such an interior space just isn't right for the 10-17, at least not so wide. I try to avoid such strongly bent lines at edges. I thus venture into strange rounded and irregular spaces, to brushy landscapes and radial interections (3 or many more lines converging centrally), and extreme closeups before a flat horizon.
I've read some commentary on rectilinear ultrawide lenses, to the effect that the proper(?) use of such is
not to stand back and capture the entirety of vast spaces and vistas, but to delve ever closer to the subject and its context. A constrained opinion, yes, but it's driving my desire for the 12-24. But do I really need it? The 10-17 can approach rectilinearity with minor defishing, with nearly the same FOV; but how do the DOFs differ, and IQ? In our lens review database
Pentax Lens Review Database - DA Series Zooms the 10-17 gets a higher rating; and the 12-24 costs MUCH more. Ah, the price vs performance is a quandry...