Samyang 35mm f/1.4 AS UMC (EOS) - Full Format Format Review / Test Report - Analysis
Lens Reviews - Canon EOS (Full Format)

Distortion

The Samyang 35mm f/1.4 shows a moderate amount of barrel distortion (~1.6%) which is usually not disturbing in field conditions.

Vignetting

In its native full format scope the Samyang lens produces a very heavy amount of light falloff at large apertures. The vignetting exceed 2.2EV (f-stops) at f/1.4 and it's still very pronounced at f/2 (1.65EV). The issue is quite well controlled at f/2.8 and not relevant anymore from f/4 onwards. This may sound like a drawback but the truth is that this is pretty much comparable to the Canon EF 35mm f/1.4 USM L.

MTF (resolution)

The Samyang lens surprised us positively in our APS-C review and it manages to keep a very high resolution level in its native full format scope as well. The center is very good at f/1.4 and both the borders and corners aren't much worse either. The contrast level is slightly reduced at this setting. There's only a slight gain in quality at f/2 but the resolution characteristic is really impressive from f/2.8 onwards. The center is pretty much outstanding between f/4 and f/8 and the outer image zone is also excellent. Diffraction effects have a slight impact at f/11 but the quality is still great here. There's only a slight amount of field curvature.

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)

Lateral CAs (color shadows) are low with an average pixel width of less than ~0.6px at the image borders. This is pretty impressive actually.

Bokeh

The quality of the bokeh (rendering of the out-of-focus blur) is, of course, a major aspect for an ultra-large aperture lens. The Samyang lens does not convince completely here. Out-of-focus highlights have a slightly nervous inner zone. The highlight shape remains pretty circular till about f/2.8 though - that's excluding the border/corner zone where the highlights suffer from the usual "cat's eyes" effect due to vignetting. The important background blur looks rather busy whereas the foreground blur is quite good.

Bokeh Fringing

Bokeh fringing is a common problem among large aperture lenses. At f/1.4 and f/2 you may be able to spot purple halos in front and green halos beyond the focus point. The issue is reduced at f/2.8 and not really visible anymore at f/4.

You may notice that the focus shift (so-called "residual spherical aberrations) is quite minimal.

Move the mouse cursor over the f-stop marks below to observe the respective LoCAs
f/1.4 f/2 f/2.8 f/4




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