Originally posted by mee The fact that you have to crop to pull out the hard vignetting is telling me they aren't fully FF compatible; If you're paying for a FF sensor, you generally want to use all of it... yes? At least, and only speaking for myself, I see it that way..
Well, I and others see it another way, Mee.
You can put a DA21 on a K-1 into the camera's crop mode, but you could also put a DA70 on and do better with a manual crop so that you get most of both lens and sensor, for instance.
Here, I shot the worst possible example - an ultrawide APS-C lens, the Sony 10-18mm f4 - on FF and got this pic on the Sydney Harbour Bridge with a little cropping. I won't buy a dedicated UWA zoom for my A7, this is fine for me, it has always had superb contrast and flare resistance: