All shots were done at f8, ISO400, 1/160s using Xenon flash, exposure adjusted using flash power control and ND filters. UV shots were done using the Baader-U filter.
[click on image to see a larger one]
Here now a VIS-UV differential using the EL-Nikkor 5.6/80mm:

and yes, quite a nice lens with quite good UV transmission and very little focus shift.
and here using the 5.6/105mm EL-Nikkor:

Quite more focus shift, but also quite good UV transmission.
For comparison here the VIS shot using the EL-Nikkor 5.6/80mm:

and using the 5.6/105mm EL-Nikkor:

Finally now the UV shot using the EL-Nikkor 5.6/80mm:

and using the 5.6/105mm EL-Nikkor:

So, if you look for a cheap lens, have an eye on these pretty good enlarger lenses!
P.S.: the 80mm EL-Nikkor (the older, chrome black full metal type) has an adapter ring on its base with outer M39x26tpi screw mount (Leica enlarger mount). Beneath it is a M25 thread for older #00 shutters. Company Schneider Optics offers adapter rings, if that one should be missing (oder code 92-013251).
P.P.S.: the filter thread of that older EL-Nikkor 80mm is 34.5mm, which is pretty uncommon, ask me if you need an adapter ring.
[A remark on the 80mm EL-Nikkor, I tried outside and infinity tests with it and unfortunately it seems to have a prominent large UV hotspot which renders it unuseable for that...]
Stay tuned, more will follow on that fascinating subject...
More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos