Photographic Tests (continued)
Most wideangle primes exhibit some vignetting, and the XF14mm is no exception. If you shoot JPEG most of the time you probably won't notice, as the X system's built-in vignetting correction more-or-less eliminates any visible effect. However if you shoot RAW, then vignetting can become much more visible, depending on whether your preferred converter attempts to correct it or not. This is illustrated below, with an image shot at F2.8. We're comparing the out-of-camera JPEG with the corresponding RAW file processed using Capture One Pro 7.1.1, which doesn't apply vignetting correction by default.
|JPEG (vignetting corrected)||RAW + Capture One 7.1 (uncorrected)|
Aside from the obvious difference in colour rendition, the RAW conversion shows substantially more vignetting than the camera's JPEG output. A key point, however, is that the relatively gradual drop-off in illumination across the frame is far less objectionable than the sudden darkening at the corners seen from some other lenses. Of course vignetting is also trivial to correct in almost any modern raw converter.
The rollover below illustrates more fully how vignetting changes across the aperture range, taken using a highly-diffusing Expodisc filter over the lens with focus set to infinity. Again we're comparing corrected out-of-camera JPEGs with what you'll see from uncorrected RAW conversions.
|F2.8, corrected||F4, corrected||F5.6, corrected||F8, corrected|
|F2.8, uncorrected||F4, uncorrected||F5.6, uncorrected||F8, uncorrected|
For those interested in the numbers, the drop in brightness at the extreme corners of the frame is shown in the graph below, comparing uncorrected files with corrected out-of-camera JPEGs across the full aperture range. Interestingly Fujifilm's in-camera processing doesn't entirely remove the vignetting, but instead reduces it to levels that you're unlikely to notice.
Specific image quality issues
As always, our studio tests are backed up by taking hundreds of photographs with the lens across a range of subjects, and examining them in detail. This allows us to confirm our studio observations, and identify any other issues which don't show up in the tests. The Fujifilm XF 14mm F2.8R puts in an extremely impressive showing, giving high quality images under a wide range of conditions.
The 14mm is, in general, extremely resistant to flare when the sun is in frame, giving high-contrast images with minimal veiling flare or ghosting. However it can occasionally run into problems when faced with light sources just outside the frame, shining obliquely onto the front element. This can result in a noticeable drop in contrast in parts of the image.
This is shown in the samples below. In the first, with the low winter sun directly in the frame, there's barely any negative effects at all. The second shows a different story though; with the sun just outside of the frame to the right, there's a significant loss of contrast at the centre of the frame. This effect is highly dependent upon the exact angle of the light - a couple of duplicate shots taken at the same time were better. But it's generally worth using the hood under such conditions to minimise the risk of flare.
|X-Pro1, F11, sun in frame||X-Pro1, F5.6, oblique light|