Samyang 10mm F2.8 ED AS NCS CS

Vignetting

The Samyang 10mm exhibits a moderate amount of vignetting overall, as is typical of ultra-wide lenses. The vignetting is most prominent at F2.8 and F3.5.  At these aperture settings, a substantial portion of the image circle is darkened, rather than just the corners.  Thus, the vignetting is best illustrated through sample images.  Click on any image to enlarge, then use your arrow keys to cycle through the different aperture settings.

Studio Samples

F2.8 F3.5
F4 F4.5
F5.6 F6.7
F8

Sky Samples

F2.8 F3.5
F4 F4.5
F5.6 F6.7
F8

When compared to the center of the frame, the brightness of the corners decays as follows:

Aperture
Corner Falloff
Aperture
Corner Falloff
F2.8 45% F3.5 30%
F4 23% F4.5 10%
F5.6 8% F6.7 6%
F8 4%

Shooting at F4.5 and smaller makes the vignetting difficult to spot in practice.  At F4 it's a toss-up, but venturing any wider will almost certainly necessitate exposure and/or vignetting corrections.  At F2.8, a good in-camera remedy is simply to overexpose by about half a stop.

While these numbers may suggest that this lens has a big problem with vignetting, in practice, it's nowhere near as bad as it might seem.  Take a look at the two sample photos below to see the effect of vignetting corrections and the severity of the vignetting itself.

before
after

At F5.6, vignetting is minimal and you most likely won't need to bother making any corrections.

before
after

At F2.8, the original photo simply appears underexposed.  So, as we mentioned earlier, it's a good idea to bump the exposure when shooting wide-open.  Brightness or levels adjustments in post should also do a good job of fixing the vignetting in this scenario.

None of the sample photos at the end of this review were in need of vignetting corrections beyond auto-levels. 

Verdict

The bottom line is that even the most severe vignetting from the Samyang 10mm can easily be corrected in post.  The vignetting cannot be ignored at F2.8 and F3.5, but as you stop down, it quickly becomes a non-issue.  Another piece of good news is that the corners are never excessively dark.

In-camera corrections would have been nice to have for this lens.


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