Today about shooting with two dedicated UV lenses, the Coastal Optical Systems / Jenoptik UV-Micro-Apo f4 / 105mm and the classic UV lens, the UV-Nikkor f4.5 / 105mm in a non-scientific photographic comparision at shooting in reflected UV, using the Baader-U filter at natural light. Both lenses were used with a long 80mm sunshade, to avoid diminished contrast, which may happen if shot without.
[click on image to see a larger one]
reflected UV images taken at f4.5:
reflected UV images taken at f8:
The UV-Nikkor 105mm image is shown on the left side, the Coastal Optical Systems 105mm on the right side. First batch was shot at f4.5, second batch at f8. White balance was done for the UV-Nikkor 105mm.
The UV-Nikkor 105mm seems to have an edge over the Coastal Optics 105mm in terms of sharpness and contrast, especially when used fully open at f4.5, but stopped down to f8 the difference gets significantly smaller, as the Coastal gains quite a bit of sharpness and also contrast.
Both lenses require about the same white balance, due to their flat UV transmission (more about that later) and show about identical exposure, with exposure times having a slight nod towards the Coastal Optics lens (1/3 stop less), which in practice is insignificant.
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