There is some slight barrel distortion at the wide end of the lens, but no signs of pincushion distortion at the telephoto end. Also, like any ultrawide-angle lens you will get some fish-eye distortion if your subject is too close to the lens. The lens' center sharpness is very good, but gets softer at the edges and in the corners. If you want your subject at their sharpest, you'll need to frame them in the center. There is some purple fringing in high-contrast areas of photos, though generally it's only visible when photos are viewed at larger sizes onscreen.