Olympus M.Zuiko Digital ED 8-25 mm f/4 PRO review - Distortion

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Olympus M.Zuiko Digital ED 8-25 mm f/4 PRO

26 October 2021

Maciej Latałło

6. Distortion

It is not easy to correct a lens with angles of view ranging from 107 to 47 degrees, so an instrument that can be used as an ultra wide-angle and a standard device at the same time. The question is how important it was for Olympus to correct that aberration – after all Mircro 4/3 system optics is known for letting camera software handle this task.

Indeed, if you examine corrected JPEG files, you find out distortion is not such a big problem. It might be called noticeable but mainly at 8 mm where its barrel variation amounts to -1.35%. After passing to 10 mm it becomes practically imperceptible, dropping to -0.32%. The higher focal lengths results are similar, at 14, 18, and 25 mm being, respectively: -0.29%, -0.23% i -0.16%.

Still, the real distortion performance can be noticed only on RAW files developed with independent software. At the 8 mm focal length the situation is really bad, with barrel distortion reaching -6.41%; at 10 mm it improves only slightly, but the result of -4.72% remains high. A more significant decrease can be seen at 14 mm, with a value of -1.88%. Distortion becomes zero near 18 mm – officially we got there +0.16%. At the 25 mm focal length you already deal with slight pincushion of +1.53%.

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Looking at the results, presented above it seems Olympus didn't give up correction of distortion completely. With such wide angles of view we've seen lenses with distortion being -8 or -9%; a level of -6.4% suggest they did try to correct it a bit. Of course it is also obvious distortion correction didn't make the list of priorities here. Pity...

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