The Helios 44-2 is actually sharp wide open, especially on APS-C....
Indeed, excuse me me for not mentioning the camera used... the D750 FF!
The Helios 44-2 needs to be used on the FF sensor both for it's swirly bokeh,(not shown here) as well as it's image quality!
Sharpness on FF is a mixed bag, and this goes for many a FF lens, but here I would dispute that the edges and corners which may be it weaker points for resolution in fact turn out to be it's strengths, simply because of FF's magnification, FF's magnication is 1/2.25 less than APSc!
That means you magnify the FF image much less than APSc image!
I go along with DXO's sharpness rating with FF against APSc, given a half decent FF lens, the overall IQ is better than APSc can offer!
Ah... that was another lens. My bad. Though I have a hard time believing that any of those old lenses are any good, especially on FF... but what do I know.