Three 365nm UV torches compared

[Cadmium]

I know this is old news to many of you, and I have posted this somewhere else before, but this seems to be a better website for this material to reside, and someone asked me about this recently, so I will re-post it here, and please pardon any redundancy.

I would like to ask any of you to please add to this topic any torch models that you have compared to the MTE. Thank you.

 

These are UV flashlights/torches. Their peak output is 365nm, similar to 'black light' (or black light blue, which peaks at 365nm), however these torches are quite powerful and should never be used without UV eye protection!

These are often used for illumination when shooting fluorescence photos (UVIVF), and useful for UV focusing.

There are quite a few of these on eBay and other places, but the functionality is not always that good.

The 365nm Nichia LED is high quality and output. Some torches are advertised as using the Nichia, but in fact they are not, and the output is not near as strong.

Here I show a quick comparison of three 365nm torches I have, using two UV meters, Solarmeter SM 5.0, and Blak-Ray J221.

The MTE torch is the best, obviously, it has a real Nichia LED, I think it is actually rated at under 1W, but out performs the 1W and 3W torches by leaps and bounds.

The UltraFire which was advertised as being a 1W Nichia LED, seems to actually be some other brand of LED, and has a fairly weak output compared to the MTE.

The Mastiff was advertised as a 3W LED (what looks like an integrated group of 3 LED's) and does seem to have more output power than the UltraFire in actual use, but is not Nichia (was not advertised as Nichia), and has very low power compared to the MTE.

The two weaker torches cost a lot less than the MTE. Since one was advertised as having a Nichia 365nm LED, and was much more affordable than the MTE, it looked like a good deal.

I hope this is a valuable demonstration for anyone that might be looking for a good 365nm UV torch.

Don't waste your money testing these out like I did, get one that really works good.

Please let me know if you have any questions.

 

 

 

By the way, the Blak-Ray J221 meter switch was set to B for these tests.

[colinbm]

The 365nm MTE UV torches are the best there is out there & don't just get one, you need a few.....

Col

[Andrea B.]

Nice & useful test, Steve.

Happy to see your reposts here.

Eventually I'll get them "tagged". When you create one, you can also tag it. Then the post appears in one of the tag indexes.

[JCDowdy]

Bumping this thread

 

Who else among us has a SolarMeter?

[Andrea B.]

Yes, me.

I have a Solartech 5.

 

My 3-level 365nm Nichia chipped flashlight has outputs as follows.

Reads are approximate as they seem to waver by a couple of degrees.

On the low setting --> 10+ mW/cm²

On the medium setting --> 70 mW/cm²

On the high setting --> ??

When I turn on the Solartech with the flashlight set to high, it seems like the measurement overshoots the limit of 199.9 mW/cm². Then the readings start flipping around all over the place. I'm guessing that this means that on high power this 365nm torch is outputting more than 200 mW/cm2 (see below for confirmation).

 

The 385nm Nichia chipped flashlight gives almost the same readings and has the same behaviour for its high setting.

 

I have a third Nichia unit which is currently stored. I'll try to check that out later.

 

The 365nm chip is an NCSU033A. This was an old one so data may have changed since then as improvements were made.

Its voltage rank was a max of 4V when run at 500 mA -- as in my flashlight.

Its power rank was a P6 which was said to output a max of 270mW at 500mA.

 

The spectrum half-width is 9 nm for the 365 (356-374) and 11 nm for the 385 (374-396).

But I note that the right-hand shoulder & tail shape is not like the left-hand shoulder & tail.

[JCDowdy]

That makes three of us at least.

 

Yes, you are overloading the meter. Over 199.9 mW they get scrambled.

 

The folks who keep reptiles have standardized on the Solarmeters to compare UV output from vitamin D terrarium lamps. Problem is, as you have observed, it is a broadband meter that cannot discern differences in wavelength.

 

Still, I think we can use them to make rough power comparisons with each other. Apples to apples, better than trying to compare using meters that might vary in spectral sensitivity.

[Andrea B.]

Yes, it was overloaded!

I've updated my post since the first writing because I found the specs on my chip

and confirmed it outputs around 270 mW/cm².

 

Apparently it is useful to know the lot number of the Nichia chip. Not all have the same output. This old 365 of mine had 3 possible lots of (max) output 230, 270 and 310 mW.

[JCDowdy]

And not all "365" nm chips are actually 365nm, and I don't mean the ones that some miscreant is simply lying about.

 

As I understand it, the bin is a range say 365-374nm would be called 365. I bought a 365 and 385 LED of the same manufacturer and according to my OL-756 spectroradiometer the "365" was actually ~374nm and my "385" was ~378nm. Very disappointing as I was going for a little variety and got nearly the same thing.

 

Within a bin number they should be comparable but unless you are buying the just the chip itself to build a source you will likely never know the bin number.

[Cadmium]

Where do you find the "3-level 365nm Nichia chipped flash" ?

[JCDowdy]

Different power settings are a function of the controller board and operated by partially pressing the tailcap button. I think the circuitry that does that may be under the tailcap button but I am not sure.

 

I have some VIS LED multimode flashlights that not only have 3 power levels but also a rapid dazzler flash and can blink out an SOS!

[JCDowdy]

Steve, do you know which Nichia LED is in the MTE? I know someone has probably posted that somewhere but I cannot recall.

 

I have visually matched the LED in my UV LED flashlight to the Nichia NCSU276A U365 which is rated at 780mW. I have to back away about 15 inches to not overload my SolarMeter. Not the top rated 365nm Nichia but not bad for a $20 to $25 UV flashlight. It is "on sale" on GearBest. The manufacturer runs his web store out of Aliexpress.com and the flashlight enthusiasts on Budgetlightforum.com seem to think highly of the guy.

 

I have measured the spectral output and keep meaning to post that info but either forget or am to busy.

[Andrea B.]

Where do you find the "3-level 365nm Nichia chipped flash" ?

 

My UV-LED flashlights were made by McGizmo on Candlepowerforums.com back in 2009 or 2010. (Don't recall exactly when.) I have two of the titanium Haiku models. They are very small.

[Cadmium]

John,

From comparing the LED's in my MTE 301 and MTE 303 to the small photos of the Nichia LED on the link below, it looks like the MTE 301 has the NCSU033B LED, and the MTE 303 has the NVSU233A LED.

You can purchase Nichia LED's directly from Nichia. I don't have a price for the NCSU276A, but the NCSU033B and NVSU233A are both about $10 @ less than 100.

http://www.nichia.co...duct/uvled.html

Compared to the this photo of 301 (left) and 301 (right).

 

By the way, to all of you that are thinking/discussing diffusers for the MTE, please try removing the entire reflector assembly from the torch barrel, and try the torch with no reflector,

this will greatly expand the light coverage footprint. I am not sure if the LED shines in all directions with the same intensity, but it sure looks like it to me.

The reflector is designed to concentrate the light in a beam, remove it and you have even scattered light, it seems like.

Just an idea for experimentation, I have not tried it with photos yet.

See this pic below to see where the reflector unscrews from the barrel.

[Andrea B.]

Within a bin number they should be comparable but unless you are buying the just the chip itself to build a source you will likely never know the bin number.

 

True, it's very unlikely that a bin number (for the LED) can be known when buying manufactured flashlights. For my "handmade" Haikus, McGizmo had the bin number and posted it for everyone to see.

 

The range for the Nichia 365 peak was 360-370 nm for the NCSU033A.

 

[Cadmium]

Within a bin number they should be comparable but unless you are buying the just the chip itself to build a source you will likely never know the bin number.

 

True, it's very unlikely that a bin number (for the LED) can be known when buying manufactured flashes. For my "handmade" Haikus, McGizmo had the bin number and posted it for everyone to see.

 

The range for the Nichia 365 peak was 360-370 nm for the NCSU033A.

 

 

Cool, but these look like they are designed to screw into a torch. You said 'flash'. Maybe you are using a slang for flashlight?

I thought you meant an actual flash.

[Andrea B.]

Oh geez -- sorry! I was being very sloppy/slangy back there! The Haikus are flashlights aka torches. I went back and corrected everything. :)

 

BTW, Steve, does your Solarmeter hold the reading when you let go of the button? Mine does not, so I would not be able to make a photo like you did with the flash on top of the meter.

Where is the sensor on your Solarmeter? On the right side of the top? Mine is in the center of the top. It looks like your flashlights are not over the center part which is why I ask? Just curious.

My Solarmeter is a model 5.0.

[Cadmium]

You are talking about the pic up at the top of this page? Yes, that is a Solarmeter 5.0, just like yours. The button is a hold-down style on/off button, I use tape. See the clear tape over the button?

I positioned the torches to produce the highest reading from each torch, this is due to the way the torches focus the beam, at that close of range it is off center (probably some better method, but works OK for me).

 

Solarmeter 5.0 is mW/cm2.

Solarmeter 5.7 is uW/cm2 (more sensitive).

(these are both UVA+B, they also make models 4.0 and 4.2 for UVA only)

http://www.solarmeter.com/

 

[Cadmium]

Where is the sensor on your Solarmeter? On the right side of the top? Mine is in the center of the top. It looks like your flashlights are not over the center part which is why I ask?

 

I tried a quick test, measuring it another way: First I removed the entire reflector assembly from the torch barrel, which leaves the bare LED (like the photo below).

Then I positioned the LED/barrel pointed directly at and level with the Solarmeter 5.0 sensor.

Each are 8cm from LED to sensor.

MTE 301 = 4.0

MTE 303 = 5.0

 

Using the 'off center - bright spot' method (as illustrated in the photo at the top of this page) I got these readings using the MTE 301 and 303:

http://www.ultraviol...dpost__p__12603

 

[Andrea B.]

oh la! No I didn't register that as tape over the button. I suppose I thought it was some kind of protective film. But anyway....thank you for the details.

 

I'm going to work my torches again to see how the beam focuses and where the highest output is. So again thank you for the details. :D

 

I wonder if the upgrade to the Solarmeter 5.7 is a good idea??

I've made good use of my Solarmeter to ensure (insofar as it is possible to do so) that during outdoor tests the amount of UV light is within a reasonable range so that, for example, one filter does not test badly against another. And also I simply enjoy measuring the UV. It is quite striking how much difference there is between the sun's UV output at high noon during winter vs. summer.

[Cadmium]

If you want to measure lower UV brightness, then the 5.7 is handy. It would work good for measuring the center of a beam at actual photography subject distance, but I have not tried that.

It works good for measuring low UV content lighting.

I have mostly used the 5.0, but if you increase the distance, then the 5.7 would work best.

[Andrea B.]

Have you ever been able to get a reading of reflected UV off a subject -- like, say, a PTFE disk?

I have not been able to do so with my 5.0, but perhaps the Solarmeter 5.7 can?