Well, I had taken apart some older equipment a while ago and have extracted the quartz fluorite optics that was hidden in it. I now have added some focusing helicoid, as well as I had some front and rear adapters made to mount it. Results of using it I had shown here and here and today will even show a few more results using it. A yellow Gazania flower in its last stages served as a model for some multispectral shots, all at approx f8-f11.
[click on image to see a larger one]
Visible light shot:
Simulated bee vision using XBV3 filter
Simulated bee vision using XBV2 filter:
Simulated bee vision using XBV6 filter:
UV using Baader-U filter:
It only has a quite small focus shift of about 1/2mm when shooting macro, but that could have been expected from a well corrected quartz fluorite lens.
UV transmittance is also quite good, as was expected from a quartz-fluorite lens and stays rather flat even beyond 300nm.
More about that used quartz fluorite lens is 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