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Nichia NCSU033B UV365nm LED

UV Lighting Fluorescence
20 replies to this topic

#1 colinbm

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Posted 04 November 2014 - 09:58

I have received an, MTE Ultra Violet UV 301 Nichia 365nm NCSU033B Model Professional Flashlight.
My first impression is that this is a powerful 365nm UV flashlight.
Fluorescing objects (photocopy paper) can be seen from a good distance away, like further then 10 metres, other natural objects like lichen can be seen from 5 metres. The circle spot of fluorescence is about 150mm.
The one aspect that bothers me is the amount of visible light that I can see, nearly white light.
Looking at the graph below from the Nichia site on page11, https://www.nichia.c.../NCSU033B-E.pdf
Is it just that this is a powerful lamp & I am seeing a very small spill into visible ?
How bright would the Fluorescence be in comparison to the 365nm UV output, would it be 30 or 50% ?
Cheers
Col

Attached Image: Nichia UV 365nm LED.jpg

#2 Alex H

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Posted 04 November 2014 - 10:33

It is powerful, and you have to use it with UV-pass filter, and you may also see some UV in 390-400 nm range...

BTW, I have three of these, and can detect see fine emission from them even when using UG11 filter on top of them. But it is normally not recorded by unmodified camera when I photograph UVIVFL.

Edited by Alex H, 04 November 2014 - 10:35.


#3 enricosavazzi

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Posted 04 November 2014 - 12:55

You can see VIS radiation directly emitted by the LED because your eyes are not recording the peak emitted at 365 nm. If your eyes had the same sensitivity to 365 nm as in the VIS range, the concentrated spot of emitted UV radiation would be blinding and would completely swamp out the VIS radiation.

I don't know how much of the incident UV radiation is re-emitted as fluorescence, but probably less than 50%. It should also vary depending on the fluorescent materials. Fluorescence is emitted in all directions (i.e., not preferentially in a specific direction related to the direction of illumination), and this by itself reduces the amount of re-emitted radiation that can be picked up by your eyes or a camera. Nonetheless, with most materials, fluorescence in the VIS range is much stronger than the "tail" of VIS radiation directly emitted by the LED, so this should not be a practical concern except in special cases.
-- Enrico Savazzi

#4 Andrea B.

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Posted 04 November 2014 - 15:28

That's a nice torch for a good price. Looking forward to seeing some cool shots, Col !!
Andrea G. Blum
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#5 Alaun

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Posted 04 November 2014 - 18:08

You might get a feeling of the "UV-power", when you direct the torch on some fabric (e.g. a towel), which was washed with a modern cleaning agent, which contain whiters.


Werner
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#6 enricosavazzi

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Posted 04 November 2014 - 19:41

White typing paper contains fluorescent chemicals, and can be used as a cheap UV detector. In fact, in sunlight, white paper is literally "whiter than white", in the sense that it emits more light than it receives from the sun. The "extra" radiation is UV-excited fluorescence in the VIS range, mostly blue.
-- Enrico Savazzi

#7 Damon

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Posted 05 November 2014 - 00:27

Excellent Col. I look forward to seeing how well this works for you.

-D

#8 colinbm

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Posted 05 November 2014 - 00:47

Thanks everybody for your responses & help.
As you say, just get out & use it :D
Yep, good advise.
Cheers
Col

#9 Shane

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Posted 05 November 2014 - 17:12

Colin

More important to me is not only how powerful the light but its uniformity. Some of the lights tend to have nasty hotspots which make it difficult to work with in photography. The 2nd and 3rd images in this link http://www.candlepow...Light-offerings demonstrate this clearly.

If possible can you provide info and examples on beam diameter and beam uniformity for instance at, 1ft, 3ft, 10ft?

thanks
Shane

#10 colinbm

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Posted 06 November 2014 - 13:49

The MTE UV 301 Flashlight, with 365nm Nichia NCSU033B diode.
Three shots of the lamp illumination, onto a 600mm ruler at 3m, 1.5m & 0.3m range.
Taken with a full spectrum converted Sigma DP2 camera with an Andrea U filter mounted in front of the lens.
Exposure times were 2 seconds at 3m, 1 second at 1.5m & 0.3 seconds at 0.3m.
All were at f10 & 100 ISO, Incandescent WB.
Cheers
Col

Attached Image: SDIM6127MTE Ultra Violet UV 301 Flashlight 365nm Nichia NCSU033B diode at 3m with AndreaU filter crop web.jpg

Attached Image: SDIM6132MTE Ultra Violet UV 301 Flashlight 365nm Nichia NCSU033B diode at 1.5m with AndreaU filter crop web.jpg

Attached Image: SDIM6134MTE Ultra Violet UV 301 Flashlight 365nm Nichia NCSU033B diode at 0.3m with AndreaU filter crop web.jpg

#11 Andrea B.

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Posted 06 November 2014 - 15:26

Nice work, Col.
I have listed this MTE 301 in Sticky #1 as an example of a useful UV-Led and linked your post here. So thanks!!

The MTE does have a brighter central area, but nothing that you can't work with by adjusting the distance and possibly painting the UV-Led over larger subjects. I've used the painting technique quite successfully for many UVIVF fotos and also some UV reflect fotos. Rotating the torch over the subject also helps diffuse strong background shadowing.

It would be interesting to try Enrico's suggestion for diffusion using that white translucent packing wrapper stuff - when/if you come across some. I'm eager to try that myself even though I have an actual diffuser for one of my torches.

[I've picked up the word 'torch' over the longer 'flashlight'. "-) Typically 'torch' isn't used in US English. But language is always evolving.]
Andrea G. Blum
Often found hanging out with flowers & bees.

#12 Shane

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Posted 06 November 2014 - 17:53

Thanks Colin that is very helpful.

#13 colinbm

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Posted 07 November 2014 - 00:26

Glad to be of help Shane,
I am pleased to see the results & the short exposure times needed.
Col

#14 Damon

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Posted 07 November 2014 - 01:36

That looks great. Nice and bright. Does it have the equivalent of a baader U on the front? What is an Andrea u filter?

-D

#15 colinbm

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Posted 07 November 2014 - 02:08

The AndreaU filter is a stacked filter of a BG38 + UG1 filters, or BG39 + UG11, I am not sure ?
But it matches very closely to the transmittance of the MTE UV 301 365nm flashlight.
Here is a graph....
http://www.fotozones...f-the-andrea-u/
Col

#16 Reed F. Curry

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Posted 09 November 2014 - 17:19

Col,
The Andrea 'U' is not a stacked filter, the glass elements are cemented together with a UV-passing optical adhesive. The glass types are not those you mention. The filter has evolved over the years and now sports a UV AR coating on the face. Here is a link to the most recent version. http://uvroptics.com/index.php?AndreaU

Thanks.

[ I apologize for what may seem like a commercial message. I simply wanted to provide up-to-date information.]

Edited by Reed F. Curry, 09 November 2014 - 17:21.

Best regards,
Reed
http://www.uvroptics.com

#17 colinbm

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Posted 10 November 2014 - 00:28

Thanks Reed
The Andrea U page doesn't have what the elements are, just the transmittance chart.
I purchased my Andrea U secondhand, so I am not aware what version it may be, but there are two elements.
I do have to wash / clean the glass surface with hydrogen peroxide, before I use it, if I haven't used it for a couple of weeks.
Cheers
Col

#18 Reed F. Curry

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Posted 10 November 2014 - 02:11

Col,
That sounds like a very early version.

The need to clean it surprises me. I used 0.5mm BK7 or BK270 cladding on both sides in most early versions. If you want to send it to me, I will add cladding to both sides for the cost of return mailing. Let me know through the email address on the UVR Optics website.

The new AR coating now protects the more corrosion sensitive glass, and the other face seems to hold up well, bare. Any glass to glass interface that can be avoided serves to keep the transmission up.
Best regards,
Reed
http://www.uvroptics.com

#19 Damon

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Posted 10 November 2014 - 02:15

Hey Col, I was wondering if you could put the Andrea "U" filter on the front of the flashlight. It would eliminate one more thing your camera has to see through. Each piece of glass in front of the camera must have some effect, albeit in this case maybe only minimal and not worth adapting.

-D

#20 colinbm

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Posted 10 November 2014 - 02:32

Thanks Reed for the offer & explanations.
I'll keep it as it is for now, thanks & appreciate the extra transmission :D
Reflection off the dichroic filters seems to be a problem with the Sigma Foveon cameras, so I'll save for the newer Andrea U with AR.
Also I feel the Andrea U is a closer match to the Mercury lamps emission line at 365nm & the Nichia 365nm NCSU033B LED & the Sigma Foveon UV response limit & of course my limited lens collection.
Cheers
Col

PS, Reed, the link for uvroptics.com is broken, but I got it here... http://www.uvroptics.../index.php?home
Col

Edited by colinbm, 10 November 2014 - 02:44.