Unlike a rectilinear lens, this lens "distorts" at the edges, so that people's faces at the edges are normal looking. A regular wide angle makes people at the edges look like they have wide faces- but not this lens. The round faces at the edges are round. Only negative thing, there is some blue fringing at the extreme edges, but if not using it fully fish-eyed solves this. The center of the lens is really sharp; the center to near edge detail is excellent. So for large groups, like a wedding line up, people from edge to edge look good, but crop out the picture to a wide panorama format so the corner distortion is cropped out. I love the results shooting with this lens in a panoramic format.
Really solid well put together lens, excellent on my KP
Ligero, compacto, hecho de buen material, silencioso, nítido, buena combinación con la Pentax KP