With that little worry out of the way, I settled down to testing and enjoying the 14mm. The 14mm is not advertised as being such, but it more then delivers that kind of performance. Now don't confuse trees tilting in at the top of a frame with not being straight line rendition. Look at a straight line at the extreme right or left of the frame if you want to check. The design of the 14mm ultra wide is such that you can capture what you see without distortion.
Sharpness is another very critical element in an ultra wide.
The DOF of the 14mm is immense and the difference between f2.8 and f11 isn't that much unless you have lots and lots and lots and lots of space in your image. The combination of corner to corner sharpness and DOF of the 14mm really comes in handy though when shooting up close. The 14mm is a small lens, much smaller than the 15f3.5 which I really like. The 14mm has a gel filter holder at the rear of the lens. You can cut and slip a thick gel like Lee's into the holder and it will stay put, but the Kodak gels are too thin.