[click on image to see a larger one]
Infinity at approx. f11:
Closeup at approx. f11:
Closeup at approx. f7:
Not that bad I'd say for something laying around, especially as it has a very small focus shift of only about 1/2mm when shooting macro.
UV transmittance is quite good, but that was expected and goes beyond 300nm rather flat..
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