[Dali]

You're trying a "very good" Zuiko and comparing it to the "superb" Zeiss Planar. You have been spoiled with the Zeiss lens.

I had an Olympus OM-20 and used the Zuiko 1,8/50 lens and was happy with it as my main small format camera until I bought an old Kodak Retina Ib with the Schneider Xenar 2,8/50. The Zuiko was sharp, but the Xenar is razor sharp.

sharp vs razor sharp... To make such statement, you need to compare lenses in the exact same situation and on various circumstances, and to eliminate any variable which could distort the result. Then you can be affirmative.

In you case and as you wrote, you did not compared a Zuiko with a Xenar but an OM20 SLR + a Zuiko vs a Retina + a Xenar which is not exactly the same thing.

take care.