ulf Posted August 21, 2017 Share Posted August 21, 2017 I have captured spectrograms of two of my Canon 199A flashes, one UV-modified and one not UV-modified. By chance I got two spectrograms with similar VIS-levels that might be interesting to compare. Spectrometer:Ocean Optics Flame UV-VIS 200-1050nm using a 30cm long Ocean Optics 400um UV-VIS fiberwith end placed approximately 40-70cm from the flashes reflector.The spectrometer and setup is not amplitude calibrated. Link to comment
Andrea B. Posted August 21, 2017 Share Posted August 21, 2017 Ulf, thank you! You might want to label your chart so that it is clear to the casual reader what the green and red lines represent?? Link to comment
ulf Posted August 21, 2017 Author Share Posted August 21, 2017 Good idea Andrea! Replaced an updated chart. Link to comment
Adrian Posted August 22, 2017 Share Posted August 22, 2017 When you say "UV modified" flash what do you mean please - plastic window removed, or UV filter over the tube?Adrian Link to comment
enricosavazzi Posted August 22, 2017 Share Posted August 22, 2017 When you say "UV modified" flash what do you mean please - plastic window removed, or UV filter over the tube?AdrianBoth spectra consist mostly of VIS radiation, so "UV modified" in this case should mean plastic window removed, but no UV-pass, VIS/cut filter added.In other types of flash, "UV modified" may mean different modifications, frequently including the replacement of the original flash tube (which absorbs UV in these cases) with one that does not absorb UV.In general, for UV imaging, it is more effective to mount a UV-pass, VIS- and NIR-filter on the camera rather than on the light source. For UV-induced fluorescence, things are of course different, and you need filtering on the light source (and sometimes camera as well). As a whole, we do not seem to have specific shorthand terms to unequivocally indicate the different types of modification of light sources. Our use of "UV modified" and "UV enabled" is rather loose and requires additional explanations to remove doubts. Perhaps we could use "full spectrum converted" (or more correctly "NUV+VIS+NIR converted", since a full electromagnetic spectrum in theory goes from gamma rays to VLF radio waves) also when talking about light sources like electronic flash, in addition to cameras. Link to comment
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