Today about something rather unique, a variable UV transmission filter (XVUV) for reflected UV photography. Well, actually one with an adjustable / variable transmission shoulder which may be steplessly adjusted by some 20nm. I tested it for the first time now using the Baader-U UV pass filter for comparison, a UV-Nikkor 105mm quartz flourite lens and my UV sensitive camera. Light was sunlight on a bright sunny day.
[click on image to see a larger one]
Ultraviolet (UV) image using Baader-U left) and shortest possible setting of the XVUV variable filter (right) - architecture:
Ultraviolet (UV) images using XVUV variable filter at different settings with shifting peak transmisison towards the right (different whitebalance as above) - architecture:
Relative transmission spectra of the XVUV variable filter at different settings, illustrating its ability to prefer shorter UV wavelengths:
This filter now allows to steplessly shift the peak transmission from about 360nm down to some 340nm, albeit with some loss of peak transmission.
I will report more about that XVUV variable UV transmission filter here later, as more testing, calibration and optimization needs to be done.
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