Fujinon XF 16mm f/1.4 R WR (Fujifilm) - Review / Test - Analysis
Lens Reviews - Fujifilm X

Distortion

The distortion level of the Fujinon is marginal at just ~0.9% (barrel-style). The lens is fully corrected thus auto-correction is not necessary here.

Vignetting

In terms of vignetting there are two sides of the story. Fujifilm uses auto-correction to control the light falloff. This works quite well with a comparatively moderate, albeit visible peak of 0.9EV (f-stops) at f/1.4. Stopping down to f/2 reduces the issue and it's not relevant anymore from f/2.8.

The original characteristic of the lens is worse than that though. Without auto-correction the vignetting reaches a heavy 2.2EV (f-stops) at f/1.4. Unsurprisingly the situation improves at f/2 and mostly resolved from f/2.8.

MTF (resolution)

High-speed lenses -especially wide-angles, tend to have a complex MTF characteristic. The Fujinon XF 16mm f/1.4 R WR delivers an above average performance (in the true sense) here. At f/1.4 the center sharpness is very good although it doesn't bite here yet. The borders are good whereas the extreme corners are soft. Stopping down to f/2 boost the center to excellent levels and recovers the corners which are now decent (other than for some field curvature). The peak quality is reached at f/4 with an excellent center and a very good outer image field. Diffraction starts to kick in at f/8 with a higher impact from f/11. The quality at f/11 remains usable but you shouldn't go beyond.

The centering quality of tested sample was Okayish - in the real world images showed some softness on the right image side. The field curvature is fairly high at f/1.4 and f/2 but dissolves beyond.

Please note that the MTF results are not directly comparable across the different systems!

Below is a simplified summary of the formal findings. The chart shows line widths per picture height (LW/PH) which can be taken as a measure for sharpness. If you want to know more about the MTF50 figures you may check out the corresponding Imatest Explanations

Chromatic Aberrations (CAs)

The lateral CAs (color shadows at hard contrast transitions) are very low with an average pixel width of 0.2-0.3px at the image borders. This is negligible. In extreme scenes you may spot some purple fringing though.

Bokeh

A key feature such a large aperture lens is the rendition of out-of-focus areas aka the "bokeh". Due to the wide-angle nature of the Fujinon we weren't able to perform the full set of tests here but we were quite pleased - even more so because wide-angle lenses aren't overly renowned for a nice out-of-focus rendition.

Out-of-focus highlights are nicely rendered at f/1.4 with some minor imperfections in the inner disc zone and slight outlining which increases towards the borders. Stopping down to f/2 reduces the outlining effect. An edgy aperture shape emerges at f/2.8 and more so at f/4.

The border highlights remain roughly intact (see below) whereas some rough "cat's eyes" are showing up in the extreme corners. This issue is comparatively underdeveloped for an ultra-wide angle lens though.

Expect some bokeh fringing at large aperture but this is normal at such speeds - see the greenish halos below for instance.