I was looking forward to getting this lens, a bit wider than my 17-40mm f4 and a bit faster. I was off to Disneyland Paris and the lens arrived a few hours before I left. The wide angle of view and lack of distortion were great. When I looked at the files though, the edges of the frames were out of focus and showed severe chromatic aberration. This was worse in the top right and lower left of the frame and whilst bad at large apertures was still apparent to an annoying degree at f11 / f16. I assumed that the lens was faulty and returned it to the retailer in Hong Kong who sent it to Canon for calibration. Canon's view was that the lens was perfect. Luckily I had returned it to the retailer within their 14 day no quibble money back period. If that is as good as it gets then I don't want it. My Sigma 15mm takes a similar angle of view and is pin sharp. Ok it is fisheye.
The 14mm is only the second Canon lens that has disappointed (the other being a 70-300 f4.5/5.6 lll). I have about 8 other Canons and they are very good. It was a huge amount of money to fork out for such a poor piece of kit. The only lens I have that cost more is the 70-200 f2.8 ll and that is a brilliant bit of glassware....