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UltravioletPhotography

Is IR supression needed with a fluorescent UV lamp?


Fandyus

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I have ordered a BeamZ fluorescent UV Lamp that takes 25W, my question is this:

I can't exactly afford a Baader U-Venus-Filter (or other outrageously expensive alternatives with supreme IR supression), and the stack of filters I use right now unfortunately leaks some visible light (stacked ZWB1 and QB39), it works alright for the most part but the QB39 cuts off a lot of the UV and also there's the aforementioned leak. So I though of hacking it the other way around and obtaining a lightsource that only emits visible and UV so that a simple UV/IR dual bandpass filter would suffice. So, does a fluorescent UV lamp emit IR, and if so how much? I can effectively supress most visible light with my ZWB1 filter alone.

I know that the quality of UV emitted by fluorescent lamps is nowhere near as uniform as the sun or converted flashes but it surely is better than LEDs, or am I wrong? I'd need to see for myself but the light sources I have ordered aren't here yet. I ultimatively aim to take UVA pictures of flowers and perhaps rocks or other interesting natural or even manmade objects. And if I can sucessfully obtain a pure UV lightsource, I will also use it for UVIVF. You don't need a wide spectrum of wavelengths for that though so I've been considering just mounting a UV/IR dual bandpass on a UV LED lightbulb.

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I don't know how much IR a BeamZ lamp emits, I am guessing not much, it should be a relatively pure UVA source. UV LEDs need to be filtered to remove visible and infrared contamination, Nichia LEDs are better but still emit some blue light.

 

In general, I recommend putting a UV-only pass filter on the lens for reflected UV photography as pretty much everything fluoresces some (even Spectralon!), and that may contaminate your image, although most things don't fluoresce that strongly.

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I don't know how much IR a BeamZ lamp emits, I am guessing not much, it should be a relatively pure UVA source. UV LEDs need to be filtered to remove visible and infrared contamination, Nichia LEDs are better but still emit some blue light.

 

In general, I recommend putting a UV-only pass filter on the lens for reflected UV photography as pretty much everything fluoresces some (even Spectralon!), and that may contaminate your image, although most things don't fluoresce that strongly.

Thank you, yes I am planning to use an IR/UV dual bandpass filter as I stated.

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Mercury fluorescent bulbs emit a ton of 708nm wavelength line and that will contaminate your UV.

A cheap alternative for you would be to stack zwb1. Four 2mm thick zwb1 filters is enough to cut the IR out and still have excellent UV response.

These can be purchased cheap. I got some 2mm 52mm zwb1 for $14 each.

https://www.ebay.com/itm/Multiple-sizes-camera-UV-Pass-Filter-ZWB1-UG11-Visible-Light-Cut-Black-Glass-/274394021287?_trksid=p2349624.m46890.l49286

 

 

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Mercury fluorescent bulbs emit a ton of 708nm wavelength line and that will contaminate your UV.

A cheap alternative for you would be to stack zwb1. Four 2mm thick zwb1 filters is enough to cut the IR out and still have excellent UV response.

These can be purchased cheap. I got some 2mm 52mm zwb1 for $14 each.

https://www.ebay.com...4.m46890.l49286

Thanks a lot for the tip! I actually already own this filter albeit just one of them. I'll keep it in mind that stacking them might be something I wanna do.

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