Originally Posted by rowan

No, it's a rectilinear lens and there's very little barrel distortion, so if you're pointing at a vertical or horizontal line it stays straight. There is another kind of issue though - perspective distortion. If you point your lens too far off the vertical horizon then the edges start leaning inwards:



It's not necessarily bad, sometimes I think those crazy diagonals add to the image:



One problem with ultra wide lenses is that subjects off-centre tend to get stretched towards the edges, which might make some content girls upset. "Does this lens make me look fat?"