There are some variant of Jupiter 9. The old silver version and range finder version is said to be sharper. Mine is black version in M39 screw mount with 15 blades.
First shot was wideopen, just like some people say, soft focus for portrait. Well I have some sharp lenses, so I'm not expect sharpness from Jupiter 9. Then I tried focus infinity.. Ooops, it doesn't reach infinity with M39-EOS adapter. I asked mflenses fellow, someone said that it's common for M39 lenses. Well, I'll let it be, it's for portrait, not landscape.
Like some other old lenses with good bokeh, sharpness isn't important. Trioplan 100/2,8 fro example. I like bokeh of this J9
|crop 100% from above|
Data from zenitcamera.com