Lenstip reviewed the new OM 90mm macro lens and concluded:
Our resolution test showed clearly that the lens has to be closed down by 1-1.5 EV to reach the peak of its performance. It means that the macro scale and the maximum performance needs an effective aperture f/8-11 so you will have to tolerate just decent resolution values near 55-65 lpmm at most. They are very far from record values amounting to 95-100 lpmm that are possible to achieve in the Micro 4/3 system.
In other words, the decision of using the f/3.5 aperture means potential users will profit from only a bit over a half of resolution that can be offered by this system.
Another misconception is a recommendation for photographers to attach the OM System M.Zuiko Digital ED 90 mm f/3.5 Macro IS PRO to a teleconverter. We are tempted by an impressive 4:1 mapping scale but nobody mentions the fact that working in its proximity you can count on the maximum effective aperture of f/16. By f/16 the Micro 4/3 system is simply useless because it provides resolution on a level of just 40-42 lpmm. Indeed, even such values are unattainable because it’s a diffraction limit for this aperture. Meanwhile for this set it constitutes the maximum relative aperture which has to be closed down by 1-3 EV in order to achieve the peak of the performance. It means in turn you would have to employ f/22-45 apertures which are completely useless in the case of the Micro 4/3 system.
I don’t doubt that a macro lens, designed for the Micro 4/3 system, that is supposed to offer better mappings than 1:1 should be faster than its full frame equivalents. Unfortunately OM Digital Solutions copy mistakes of Olympus and consequently offer slower lenses, destroying all possible assets of the use of a smaller sensor. I fail to understand such a policy…
When it comes to the tested model, so the OM System M.Zuiko Digital ED 90 mm f/3.5 Macro IS PRO, it performed exactly as we expected, delivering good quality images up from the maximum relative aperture, very good on slight stopping down. Its parameters didn’t allow it to do more but we’ve already covered that topic…
Lenstip is disappointed that OM Digital didn’t make the lens faster. I know it would have been an even bigger lens but maybe this would have made more sense?