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Lens review

Olympus M.Zuiko Digital ED 17 mm f/1.2 PRO

29 January 2019
Maciej Latałło

5. Chromatic and spherical aberration

Chromatic aberration

Fast wide-angle lenses sometimes experience serious problems when it comes to correction of longitudinal chromatic aberration. The tested Olympus 1.2/17 doesn’t have them; still it doesn’t mean that aberration is corrected in a perfect way. You can notice slight colouring of out-of-focus images, especially by f/1.2, but the problem shouldn’t be called huge or even medium so we don’t have any serious reservations in this area.

Olympus M.Zuiko Digital ED 17 mm f/1.2 PRO - Chromatic and spherical aberration


The graph concerning lateral chromatic aberration, depending on aperture values, presents a picture below.

Olympus M.Zuiko Digital ED 17 mm f/1.2 PRO - Chromatic and spherical aberration

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You can notice a delicate increase from less than 0.05% at the maximum relative aperture to a bit over 0.07% for the apertures ranging from f/5.6 to f/16. That range of aberration results fits our definition of low levels so we can say the M.Zuiko Digital ED 17 mm f/1.2 PRO doesn’t have problems with correcting lateral chromatic aberration.

Olympus E-M5 II, RAW, f/1.2 Olympus E-M5 II, RAW, f/11.0
Olympus M.Zuiko Digital ED 17 mm f/1.2 PRO - Chromatic and spherical aberration Olympus M.Zuiko Digital ED 17 mm f/1.2 PRO - Chromatic and spherical aberration


Spherical aberration

When it comes to spherical aberration it is corrected quite well; anyway, as you might notice while glancing at the first image of this chapter, we didn’t see any traces of focus shift effect. Still the influence of this aberration becomes noticeable if you look at photos of defocused light points. The circle reached before the focus has soft edges and the one after the focus features a distinct, light rim. It is a classic symptom of this type of aberration and it means the optics of the lens doesn’t correct it perfectly well. It’s hard to say whether it is a deliberate attempt to provide nicer look of out-of-focus areas or perhaps a price to be paid for a better correction of other optical aberrations.

Olympus E-M5 II, f/1.2, in front of Olympus E-M5 II, f/1.2, behind
Olympus M.Zuiko Digital ED 17 mm f/1.2 PRO - Chromatic and spherical aberration Olympus M.Zuiko Digital ED 17 mm f/1.2 PRO - Chromatic and spherical aberration