These are the first tests I shot with the new Fujifilm XF 14mm f/2.8R wide-angle on my X-E1. All shots were processed in Phase One's Capture One Pro v7.02 with some slight post-processing in Adobe Lightroom v4.3. Some perspective distortion correction was applied on a few of the night shots, but no corrections for barrel distortion were applied, nor were they needed. Note that it was windy, so there is some movement and blur in trees and foliage on some of the night shots.
The XF 14mm is equivalent to 21mm on a full-frame body and quite simply, this new lens is very nearly the best ultra-wide prime I have ever shot with. The only lens I've used that is in the same league optically, and that is wider than 24mm (full-frame equivalent), is Canon's EF 17mm f/4L TS-E and it, of course, is manual focus as well as big, heavy and very expensive. As mentioned, none of these photos have had any barrel distortion correction. The XF 14mm seems essentially free from any sort of field curvature, there is virtually no detectable chromatic aberration and only the barest hint of purple fringing along extremely high-contrast boundaries, for example, with power lines or branches against a white, blown out sky. Even the edges of the frame are essentially tack sharp wide open at f/2.8, with the extreme corners following by f/4 already. There is also no green/magenta bokeh fringing and what little background blur one can get with an ultra-wide at f/2.8 (see frame 9), looks to be very smooth and pleasing as well. Internal reflections seem well controlled, contrast is good... although I have yet to see how it performs in daylight with the sun shining on the front element or when the sun is included in the frame. The only noticeable flare spots I saw in all these photos that were due to the lens itself, are below and the bright light in frame 22 and over the pillar in frame 33, although there are a few shots where there is some reflection off the inside of the front protective filter (frame 32 for example).
The resolution of this lens is so consistent and even, that one can take a series of tripod shots, zoom into an extreme corner and flip through images shot from f/4 to f/11 and there is virtually no detectable change or improvement in corner sharpness, presuming there are no depth of field issues there of course. Only at f/2.8 in the extreme corners, is there a hint of contrast and sharpness loss, and beyond f/11, diffraction starts taking a visible toll across the entire frame. I would say it is actually sharpest in the f/4 to 5.6 range, which is truly superb for such a wide-angle lens. The XF 14mm f/2.8 R has exceeded my wildest dreams and is truly an exceptional performer!