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Lens review

Canon EF 50 mm f/1.8 STM

11 July 2015
Szymon Starczewski

5. Chromatic and spherical aberration

Chromatic aberration

In the case of the longitudinal chromatic aberration when you compare the tested lens to its predecessor it would be difficult to notice any difference. In both cases that aberration is noticeable but you can’t speak about high or bothersome levels.

Canon EF 50 mm f/1.8 STM - Chromatic and spherical aberration


The graph below presents the levels the lateral chromatic aberration in correlation with the aperture values and the detector.

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Canon EF 50 mm f/1.8 STM - Chromatic and spherical aberration


First of all it is a very good performance because the aberration never gets close to even a medium level. Overall the graph is very similar to the one you saw in the Canon 1.8/50 II test; still values were by about 0.01% lower. Such a difference falls within a margin of measurement error so we assess equally way the way both lenses fare in this category.

Canon 5D III, f/1.8 Canon 5D III, f/8.0
Canon EF 50 mm f/1.8 STM - Chromatic and spherical aberration Canon EF 50 mm f/1.8 STM - Chromatic and spherical aberration


Spherical aberration

In this chapter we can virtually repeat everything we included in the Canon EF 50 MM F/1.8 II test because the images you get here are almost identical. The Canon EF 50 mm f/1.8 STM doesn’t have any “focus shift” effect so its spherical aberration level cannot be very high. Still it is difficult to say whether that aberration is corrected in a perfect or just merely very good way. It seems some problems might exist and the photos below are the proof. There are noticeable differences in the appearance of the edge of the circle – in one case you see a rim and in the other there is some brightness loss near the edge. It is a classic manifestation of spherical aberration which hasn’t been corrected in a proper way.

Canon 5D III, f/1.8, in front of Canon 5D III, f/1.8, behind
Canon EF 50 mm f/1.8 STM - Chromatic and spherical aberration Canon EF 50 mm f/1.8 STM - Chromatic and spherical aberration