Handheld brick wall. Minor vignetting and some distortion but very good for wide open IMO.

[house]

Yep looks sharp for f2.8 at 11mm! Your lower right looks slightly oof but you're not quite square to the wall which could be the cause. In one of the Pentax interviews from a long time ago they said that UWA's should have some distortion to look natural. I'm not to happy about this line of thinking but for anything but architecture it's probably true. Funny thing is that my peeve with distortion is less the distortion, which can be fixed in post, but the fact that it makes it difficult to hold the camera perfectly square to a building or like in this case a wall.

[Ex Finn.]

but you're not quite square to the wall

I know I was off a tad and it does show for sure.