Hi,
DxO-mark has data for all apertures. In general when stopping down beyond optimum aperture there will not be a lot of difference between lenses as diffraction is the limiting factor. To be more exact, you would meed to multiply MTF with the undiffracted lens with the MTF of diffraction, so a very good lens would have some advantage over a lesser lens even if stopped down.
MTF charts are no good comparison, unless the conditions are specified.
The DxO data seems to be both good and reliable, but they unfortunately are not very clear in the description of the methods used.
The main advantage of the Otus may be the almost total elimination of axial chromatic aberration at maximum aperture. That is nothing that would be obvious in the usual MTF curves.
Best regards
Erik
I have not been able to find MTF charts for these 50mm lenses, other than wide open, f2 and f4.
Since I usually shoot at smaller apertures, can anyone direct me to any tests of these two lenses across all apertures?
Thanks.