Originally posted by lesmore49 Thanks that's what I wanted to know...the field of view. One mm is not much more than my 28-105 FF lens, interesting to know.
No. I think you have fundamentally misunderstood this. If your DA12-24 works on the K-1 from 18mm it is giving you a FULL FRAME 18mm field of view. So it is MUCH wider than the DFA28-105.
The image quality in the corners is another question. Of the crop lenses I have tested on the K-1, the DA35 macro covers the full frame at close focal distances, but the IQ falloff at the edges is dramatic. I consider it to be crop lens only. Likewise, the DA10-17 fisheye covers the full frame from about 14-15mm, but the IQ at the periphery is so poor you're better off shooting in crop mode at 10mm to get the same field of view.
DA15 and DA21 aren't within a bull's roar of covering FF, nor is the DA*50-135 (at any focal length). The DA55-300 comes pretty close longer than around 190mm, but I prefer crop mode because I only use it for reach and like having AF sensors all the way to the edge of the viewfinder frame.
The DA*55 is fantastic on FF. The IQ is superb, but stopped right down the hood does just creep into the extreme corners. As I generally use it at wider apertures it's rarely an issue, and a tiny crop eliminates it when it is.