A while ago I tested it against the Coastal Optics Micro Apo 105mm and the Nikon UV Nikkor 105mm and it perfomed very well.
[click on image gets you a larger image]
Today now the spectrometric results in comparison to the Kuribayashi 3.5/35mm lens, one of the best performing "normal" lenses for UV:
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It gets pretty clear that the B&L lens has a very high UV performance, at 365nm it transmits 74%, whereas the Kuribayashi has 80%, so very close to it. A very useful long focal length lens for reflected UV.
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