These UV images were shot at F4 (F4.5 in Focotar-II 50mm and F5.6 in El-Nikkor 80mm) and F8, and cropped into the petal area to our right where the focus was set on.
Summary of sharpness:
Coastal Optics is by far the sharpest wide open. The Soligor 35mm F3.5 9xxxxx series @ F4 is pretty sharp and useable, and stands out compared to the rest.
The enlarger lenses are also pretty sharp wide open, although the Leica and El-Nikkor have smaller apertures; in fact the Leica 50mm was closer in light transmission to F5.6 at its maximum aperture when comparing the shutter speeds used for the focus shift test.
The other 35mm F3.5 lenses do need to be stopped down to about F8, to increase sharpness and contrast for UV-imaging.