Wednesday, May 25, 2011

UVIR camera relative channel sensitivity for UV

(currently being reworked)

Full spectrum camera spectral response; simple test

To figure out the approximate spectral response of my full spectrum converted camera, I played around a bit with some gratings and my stabilized, continuous Xenon light source. I also found a linear spectra of my Xenon lamp, so with its help an approximate calibration of the recorded spectra is possible.

The first line is the Xenon spectra, the second the unfiltered spectra as recorded by the UV sensitive camera, the third line filtered through a Didymium calibration filter.

[click on image to see a larger one]




So from that and the color tests I published before, I would estimate that this full spectrum camera has a 320nm - 1000nm UV-VIS-NIR response. Actually I think it is more, as in such an image the exposure range limits the recording of fainter responses at the ends of the spectrum.

Found some better software which allows to read out such optical spectra. Here the results of using such:


On top the spectra as taken by photo, underneath the read out and calibrated spectra using known data high pressure Xenon spectra. The x-axis is in Angstroms, so knowing that 10A equals 1nm, it is easy to understand.

Again, please remember that the grating used was not really made for UV, but for VIS + NIR, so no wonder the spectra ends around 380nm. The real sensitivity to UV of that converted camera is quite higher, but I haven't found its limits yet.


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

A few quartz flourite UV lenses on the bench

As I was taking some measurements with the Coastal Optics UV-VIS-NIR Apo 60mm, I thought why not also testing a few other fully color-corrected lenses while I'm at it... (forgot the Coastal Optics 105mm, unfortunately...)

[click on image to see a larger one]


[validity: approx 310 - 750nm]
Interesting to note, how similar the older designs (Zeiss UV-Sonnar 105mm and LOMO UFAR-12 41mm) are, but the Pentax Ultra Achromatic Takumar 85mm has a notch in terms of transmission. Then comes the UV-Nikkor 105mm and the newer CERCO 94mm; the newest and best being the most advanced development, the Coastal Optics UV-VIS-NIR Apo 60mm.

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