I made a comparison with three enlarging lenses EL-Nikkor N 50mm f/2.8, Focotar 50mm f/4.5 and Rodagon 50mm f/2.8. Mounted normally, non-reversed.
The subject was some lichen on a small branch. Magnification around 1:1 with small variation coming from my different DIY lens mountings. I tried to focus at the greenish area in the yellow circle.

There's small variation in brightnes too although the exposure time was the same - camera at M mode - and aperture was set to the same number 8 with every lense's aperture ring. Nikkor was almost 1/3 stop brighter than the two others.
I thought to compare the Straight Out off Camera Jpegs but due to that exposure difference and CA problems in Nikkor I used RAWs processed them in my usual way in RawTherapee.
Here EL-Nikkor SOOC

EL-Nikkor converted from raw

Focotar from raw

Rodagon from raw

There's RT's automatic CA correction in every pic and the same amount of sharpening; in EL-Nikkor picture I manually added CA correction until it looked good. CA correction made it also a little sharper than the jpeg from camera; still not as sharp as the others.