Sony E 35mm f/1.8 OSS (SEL-35F18) - Review / Lens Test Report - Analysis
Lens Reviews - Sony NEX

Distortion

The Sony lens produces only a marginal amount of barrel distortion (~0.3%) so it's fairly obvious that it hasn't been under-designed like some lenses in other mirrorless systems.

Vignetting

The light falloff at max. aperture is rather hefty at ~1.6 EV (f-stops). Stopping down to f/2.2 resolves some of the issue and the vignetting is mostly gone from f/4 onward. However, this is a little "late".

MTF (resolution)

So far we weren't overly impressed by most Sony NEX lenses but the E 35mm f/1.8 OSS came as a positive surprise actually. At f/1.8 the contrast is somewhat reduced but the center resolution is very decent and even the outer image region provides good results. Stopping down to f/2.2 boosts both contrast as well as the overall sharpness. There is a bit of field curvature at such large apertures though. At f/4, the lens is essentially as good as it gets on a 24 megapixel sensor. The center is nothing short of outstanding here and the outer image field reaches very good to excellent levels. Diffraction has a limiting effect beyond but the results remain very good at f/8.

The centering quality of the tested sample was acceptable ... after a repair. By now we dare to state that this is another indication that Sony's lens manufacturing is still lacking sufficient quality control measures - despite comparatively high lens prices. Over the recent years we have been facing way more outliers than e.g. from Canon or Nikon.

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 Sony lens produces a quite low amount of lateral CA (color shadows at harsh contrast transitions) of just under 1px at the image borders. This is pretty good on such a high resolution sensor.

Bokeh

One of the primary usage scenarios for a large aperture lens is to separate the main subject from its surroundings. In such an image the quality of the bokeh (out-of-focus blur) is of major significance.

The Sony E 35mm f/1.8 OSS delivers pretty good results here. Out-of-focus highlights have a circular shape but the rendition in the discs is slightly "onion-like" - possibly a side effect from the aspherical elements in the optical design. At f/2.8, you can spot the first traces of the aperture shape but this is a normal effect actually.

The rendition in the critical focus transition zone is quite smooth especially for a 35mm lens. The more critical background blur is somewhat better than slightly more nervous foreground.

Bokeh Fringing / Longitudinal Chromatic Aberrations (LoCA)

Bokeh fringing is a common characteristic with fast glass. It's visible as halos of different colors in out-of-focus areas - magenta (red + blue) in front of the focus point and green beyond.

The Sony lens exhibits a significant amount from f/1.8 all the way up to f/4. While we can't really object at large apertures, the issue is higher than expected at f/4.

Move the mouse cursor over the f-stop marks below to observe the respective LoCAs
f/1.8 f/2.2 f/2.8 f/4




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