Here now a test using that previously mentioned Petri Kuribayashi f3.5/35mm lens when used with the standard UV transmission filter, the Baader-U as well as my shorter wave Jupiter-U filter, compared to the Noflexar f3.5/35mm lens.
[click on image to see a larger one]
When using the Baader-U filter, the Kuri 35mm has a peak transmission of about 58% at 362nm, wheras the Noflexar 35mm shows one of about 45% at 365nm, that is a gain of about 0.4 stops for the Kuri 35mm.
When using the Jupiter-U filter, the Kuri 35mm has a peak transmission of about 43% at 350nm, wheras the Noflexar 35mm shows one of about 30% at 358nm, that is a gain of about 0.5 stops for the Kuri 35mm, based on its deeper reach into UV.
There is a part III about this lens HERE.
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