colinbm Posted March 30, 2021 Share Posted March 30, 2021 WOW, spectrum of an uncovered Godox AD200 flash.... Link to comment
Stefano Posted March 30, 2021 Share Posted March 30, 2021 Well, if that is real, you have a big problem. But I think the real reason for that peak is the spectrometer, although I don't know what it could be. Some members who know how to use a spectrometer will surely be able to help you more than me. Link to comment
colinbm Posted March 30, 2021 Author Share Posted March 30, 2021 Obviously the UVC peak is useful for UVC fluorescence.. ;-)But I haven't seen a Xenon spectrum like this before ? Link to comment
ulf Posted March 30, 2021 Share Posted March 30, 2021 Col, I think the spectrometer is to blame here. I made some investigations about the AD-200 in this topic:https://www.ultravioletphotography.com/content/index.php/topic/3206-is-the-godox-ad200-ttl-pocket-flash-kit-uv-convertable/page__hl__godox__fromsearch__1 Link to comment
Bill De Jager Posted March 31, 2021 Share Posted March 31, 2021 I'd been thinking that maybe the model number indicated its lower cutoff - 200 nm. Link to comment
colinbm Posted April 22, 2021 Author Share Posted April 22, 2021 I have tried again to get a proper spectrum of the bare Godox AD200, this seems to be more accurate. Link to comment
JCDowdy Posted April 22, 2021 Share Posted April 22, 2021 This is an fine example of the limitations of such instruments and has been discussed at length on this forum. Single fixed grating, linear array detector spectrometers are known to have unacceptable stray light rejection at short wavelengths. Every bit of that huge peak below 325nm in the first post is artefact. Link to comment
colinbm Posted April 23, 2021 Author Share Posted April 23, 2021 This is an fine example of the limitations of such instruments and has been discussed at length on this forum. Single fixed grating, linear array detector spectrometers are known to have unacceptable stray light rejection at short wavelengths. Every bit of that huge peak below 325nm in the first post is artefact. Thanks JohnI have asked the manufacturer about the truncated data at the UV end & this is their response, below, which I now understand better & it is only a small problem that I can cope with now that I am better informed.The solution is a specialist UVC spectroscope.... " For the sun light, they do have big difference in the radiance ratio of Visible light and UV light.Because the CCD dynamic range, it is 1300:1, so if UV light ratio is under 0.5% of Visible light, then it will not be shown.It means compare Visible light and UV light , the UV light is very little little radiance.(100 to 0.5) " Link to comment
dabateman Posted April 23, 2021 Share Posted April 23, 2021 I have tried again to get a proper spectrum of the bare Godox AD200, this seems to be more accurate. Oh no Colin you missed out on your chance for a research publication. Remember this:https://www.ultravioletphotography.com/content/index.php/topic/4445-paper-from-a-bad-science-journal-deadly-ultraviolet-uv-c-and-uv-b-penetration-to-earth%e2%80%99s-surface/ But you need to give a tree a sunburn with the flash. That would have clinched it. Link to comment
colinbm Posted April 24, 2021 Author Share Posted April 24, 2021 I missed my chance to fly with the eagles, I'll just have to be happy on the ground with all the turkeys.... Link to comment
Andrea B. Posted April 24, 2021 Share Posted April 24, 2021 https://youtube.com/EhxVexWtE-4 All us turkeys have a goooood time. Link to comment
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