I now own a HD DA 20-40 and have been testing it on the officially unsupported FF K-1. Here are some recent workings. I have to say I find it quite usable at a lot of varying focal lengths and apertures. Very pleased as I now gain a small zoom WR lens to add to my collection for those rainy days.
Pixelshifted, non cropped.
Pixel peepers, you are welcome; live.staticflickr.com/65535/33990516118_a9af6e022e_o_d.jpg