Depth of field is an optical illusion. The blur is smaller than the human eye can resolve when looking at the final image. It's not so incredibly wide-angle, and apart from the window frame there's nothing particularly close to the "camera". Stopped right down, and on a tripod, it doesn't look impossible. And it's hard to tell, but the distant objects don't look quite sharp. Which is something I've done with my camera when there's a little haze.