Best Basic Gear: Goggles, Filters, Torches

[Andrea B.]

ORIGINAL DATE: 2021 August 29

UPDATE 1 Aug 2023. Removed UVR Optics NIR-Block because not strong enough at OD2 in some regions. Replaced with reccie for BG39.

UPDATE: 22 May 2023. Added suggestion for finding Schott/Hoya UV dual bandpass glass now that UVIR*Optics has gone out of business.

UPDATE: 22 May 2023. Added AndreaU MK II and UVBplus to Name Brand Filter list.\

UPDATE: 9 April 2024:  Added warning about Tangsinuo not providing the filter thickness requested by the customer.

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This is a "Best" list for some basic gear. Be sure to see the 2nd post for the UV-pass filters.

 

• UVP and its Owner/Admins have no monetary affiliation with any vendor.
  UVP and its Owner/Admins are "gear neutral". Use what you love using!

• All links are for your information only and do not constitute a vendor recommendation.
  Search around for the best prices.

• The recommendations here are for basic beginner gear. Your needs might be more specific or more advanced. If so, please consult the Stickies and check recent forum discussions.

 

Note that there are NO camera or lens recommendations!! 

Everybody including their 3rd cousin's brother-in-law's mother's best friend has an opinion about UV-capable lenses and cameras and those opinions are all different. Try this search tag to find recent forum discussions: Camera Search Tag.

In reflected UV photography, just as in Visible photography, we can say that better sensors do give better files. However, artistry in UV photography can be accomplished with any UV gear.

 

 

SHOPPING WARNING:  If you find some name-brand gear online at a price which seems too good to be true, then it is probably some imitation being passed off as authentic. Please shop only at a reputable online store. As one example, Alibaba was recently selling fake Zeiss T* UV-blocking filters. 

 

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SAFETY

Best UV Protection Glasses or Goggles:

Yes, UV light is dangerous! Ever gotten a sunburn? Ever had snow-blindness?

And UV damage to eyes & skin is cumulative.

Look for at least 99% blockage and wrap-around protection in the safety glasses you choose.

Here are two options.

 

McMaster-Carr 99.9% UV Protection Rating

The linked page shows wraparounds, panoramics which fit around the temple, and ventilated goggles. Prices range from $9 to $30.

Here is a specific link for yellow or orange tinted goggles: https://www.mcmaster.com/eye-protectors/lens-color~yellow/lens-color~orange/uv-protection-rating~99-0-/

Here is a specific link for ventilated goggles: https://www.mcmaster.com/eye-protectors/lens-color~yellow/lens-color~orange/uv-protection-rating~99-0-/lens-style~panoramic/lens-properties~ventilated/

 

UVEX also makes very good protective glasses/goggles. The link is to the manufacturer's website which has scads of info about sports & safety glasses. To buy UVEX goggles it's probably best to google around for the best deal on Amazon or other websites.

 

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LIGHTING

Best UV Illumination:  SUNLIGHT !! "-)

There's more UV in Sunlight at high altitudes. There's more UV in Sunlight in the middle of the day. There's more UV in Sunlight in summer. So, mountain top at high noon in July and you're good to go! However, if Sunlight is missing at sea level in the early morning in December, then see the next entry.

 

Next Best UV Illumination: UV-Flash

The Xenon flash tube must be uncoated.

The Canon 199A is a current UVP favorite for modding into a UV-flash. But there are other possibilities. Use the next link.

Lighting TAG Search

Click that lighting tag search for further info about UV lighting. There will be info about UV-flashes in there somewhere. Ordinary Xenon flashes can be modified (DIY) with filters to pass only UV light.

**WARNING**  Please remember that flash units have murderous capacitors, so do not fry yourself dead by wonking around in the wrong part of the flash unit while changing the filtration. Mod a flash unit at your own risk!! 

 

Best Basic 365-nm UV-Led Torch: Convoy S2+ UV with Nichia Chip A

NOTE: Recently the no-name "Nemo" torch has been more popular with the UVP Membership.

Nemo search on UVP.  Nemo search on Google.

 

A UV-Led torch is used to supply light for

• focus illumination on the subject while focusing through Live View, or
• inducing Visible or IR fluorescence in a dark room, or
• light-painting a reflected UV subject during a long exposure.

 

In the past Nichia was considered the best 365nm UV-Led Chip maker. But I don't think you should worry too much about either the brand or the grade of UV-Led chip because we are looking mostly for enough output (wattage). You might need two torches depending on how you make use of them. If you can find info about the UV-Led torch chip you are considering buying, look for an A grade UV-Led for best results.

 

TORCH NOTE 1: The Convoy S2+ Nichia A torches are well-made, well regarded and meet stated specifications. If you want something less expensive, then you can take your chances with the unbranded UV torches sold on Ebay. Many of these do not meet their stated specifications.

Please check the recent forum discussions for advice on unbranded torches!

 

TORCH NOTE 2: That third use of a UV torch there in the bullet list? Let me point out the following: it's not easy to make a reflected UV photograph using only a UV torch. Exposures are long and results are noisy. The best reflected UV photos are made in strong sunlight or using a Xenon flash with a UV-pass filter. Sunlight and UV-flash produce more false color due to the wider range of UV.

 

Best UV Light for Beginners, Intermediates and Advanced:  UVA and UVB ONLY!!

As for UVC, we say NO, just NO. UVC is too dangerous. 

And it is very difficult to find the filters, lenses and cameras which can record below 300 nm. There's scarcely any UVC light in sunlight anyway. So where would you find illumination? You don't want to even go near those 254 nm sanitizing bulbs which will break your DNA. Frankly, IMHO, what I've seen so far in UVC photography is not particularly impressive anyway. UVC is not where the beauty of reflected UV photography lies. It just isn't. 

If you must play with UVC, please remember that you have been warned by UltravioletPhotography.com NOT to do this. UltravioletPhotography.com cannot and will not accept any liability for damages you may incur from UVC light.

 

Best Filter for Basic 365-nm UV-Led Torch:  Hoya U-340 x 2.0 mm

LINK to Transmission Chart

LEDs have a fairly narrow output, but using this filter on your torch will ensure there is no violet/blue visible contamination when the torch is being used for inducing visible fluorescence. You do not need to filter your torch for non-fluorescent work.

 

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FILTERS

Best UV/IR-Blocker for making Visible Light photos with Full-Spectrum Camera

There will be opportunities to use your full-spectrum conversion in visible light. So replacing the removed internal UV/IR blocking will be necessary.

Kolari Hot Mirror Pro 2  Best, IMHO.

Link to UV/IR-Blocker tests
Kolari's newest UV/IR-Blocker has a transmission curve which matches the transmission curves of most cameras internal filtration. White balance in-camera should give you good color. Any small deviations are easily tweaked in an app or by using a color correction profile.

OR

Schott BG38 x 2.0mm 

OR

B+W 038 + [Longpass UV-Blocker]

Filter stacks like this are somewhat more prone to flare & ghosting in backlit scenarios.

Your choices for the longpass UV-Blocking component are: 

• Schott GG400 or Schott GG420
  Most camera makers' internal UV-cut filtration begins somewhere between 400-420 nm.
• Filter stacks work better if one of the components has AR-coating. That costs more though.
• Zeiss T* UV Filter
  This filter is regarded by many as the best UV blocker. It is AR-coated and cuts UV very well starting between 400-410 nm.

 

Best IR-Blocker for making Reflected-UV photos with Full-Spectrum Camera

Stack one of these over your UV-pass filter for extra protection against IR contamination.

Schott S8612 x 2.0 mm

LINK to IR-Blocker Transmission Charts for 2.0 mm

Depending on the thickness of your dual bandpass filter, you might find that a thinner S8612 will suffice. But a 2.0 is almost universally useful and is the best thickness for your first purchase. Try to get one with AR coating. Recently S8612 has been difficult to find.

OR

Schott BG39 x 2.0 mm

OR

B+W 039

S8612 has become difficult to find, so look for this next best IR-blocker for working in UV with a full-spectrum camera.

 

Best Chinese ZWB and Other Filters: Tangsinuo Technology

^{This currently reputable vendor recommendation is subject to change.}

 

^{UPDATE 9 April 2024:  Recently a UVP member has reported that the thicknesses of filters received from Tangsinuo have not matched the requested thicknesses in the order. For example, one filter was .5 mm thinner than requested. Please INSIST when ordering that your requested thickness is supplied or else you will give Tangsinuo a bad review and file a complaint with Ebay.} 

 

LINK to Review by JMC

Please remember that Chinese manufacturing is not currently subject to the same standards which apply elsewhere. Striations, pits and visible leakage have been seen with some of the Ebay Chinese filter purchases. And some of the filters don't quite match the expected transmission in either peaks or rate. But these equivalents of UV dual bandpass filters and BG filters are very much less expensive than the high quality Schott or Hoya glass, so most beginners use Chinese filters to get started.

 

FILTERS is continued in the next post.

 

[Andrea B.]

UPDATES:  

22 May 2023 Discussed disappearance of Ebay vendor UVIR*Optics.

26 May 2023 

9 April 2024:  Added warning about Tangsinuo not providing the filter thickness requested by the customer.

 

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Best Beginner UV-Pass Filters

 

I am going waaaaay out on a limb here by offering up a list of the best UV-pass filter(s) for beginners in reflected UV photography. Please check the most recent discussions on the forum and ask questions before you buy a UV-pass filter. I'm out on the limb because there are a lot of personal preference and budget considerations which are different for everyone.

 

Dual Bandpass Glass

 

All UV-pass filter glass is actually dual bandpass glass which transmits both UV and IR. So to make a good UV-pass filter, the contaminating IR transmission must be blocked by applying dielectric coatings to the dual bandpass substrate or by stacking a layer of blue-green IR-blocking glass over the dual bandpass substrate.

 

Do you have a lens with some "reach" past 350 nm?  If so, then go for something in the UG11/U-340/ZWB1 group. Otherwise, the UG1/U-360/ZWB2 will serve you better. At the end are some brand name filters which incorporate IR-blocking into the finished product.

 

 

The dual bandpass glass equivalencies are:

• ZWB1 ~ Schott UG11 ~ Hoya U-340
• ZWB2 ~ Schott UG1  ~ Hoya U-360
• ZWB3 ~ Schott UG5 ~ Hoya U-330

 

Please understand that the use of the word "equivalencies" does not imply equality. Always check transmission charts. See the first post for the currently recommended Ebay vendor for ZWB and other Chinese filter glass.

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Schott/Hoya Stacks__________________________________________________

See UVIR*Optics on Ebay for authentic Schott or Hoya filters.

22 May 2023: This Ebay vendor seems to have gone out of business. To obtain Schott or Hoya filters, you might try Edmund Optics. Here is a link to their page for Bandpass filters:  LINKIE

1 Aug 2023:  Given that S8612 has become difficult to find, the next best IR-blocker is probably Schott BG39.

 

I have used all of the following stacks successfully. With S8612, you get very good IR-blocking from stacks like this as compared to the name brand filters listed below. I have not yet experimented with BG39 blocking. The cost of strong IR-blocking is slightly longer exposure times due to reduced transmission through 4.0 mm of glass. Not really a problem though because ISO can be boosted in newer cameras without too incurring too much noise.

 

• Schott UG11 x 2.0 mm + Schott S8612 x 2.0 mm (or Schott BG39 x 2.0 mm)
  358FWHM50 approx, 55% at peak, min OD5
  OR
• Hoya U-340 x 2.0 mm + Schott S8612 x 2.0 mm (or Schott BG39 x 2.0 mm)
  358FWHM50 approx, 57% at peak, min OD5

 

• Schott UG1 x 2.0 mm + Schott S8612 x 2.0 mm (or Schott BG39 x 2.0 mm)
  360FWHM50 approx, 52% at peak, min OD6.
  A thinner stack might have a very minor, harmless violet leak but not past 405 nm.
  Some small violet passage does not really affect a UV photo, IMHO.
• OR
• Hoya U-360 x 2.0 mm + Schott S8612 x 2.0 mm (or Schott BG39 x 2.0 mm)
  363FWHM50 approx, 58% at peak, min OD6.
  A thinner stack might have a very minor, harmless violet leak but not past 405 nm.

Stack prices:  Prices depend on diameter size, thickness and current availability. 
 
THICKNESS NOTE: There are other thickness combinations of these dual bandpass and IR-blocker filters which transmit a bit higher and maintain a high OD 5 blocking level, but we recommend the S8612 x 2.0 mm as a beginning, reusable IR-blocker. 

 

WARNING NOTE:  Schott and Hoya filter glass is uncoated. UG11, U-340 and S8612 and other BG glass are prone to oxidation and must be regularly inspected and cleaned. Some vendors offer protective coatings or AR coatings.

 

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ZWB Bargain Stacks__________________________________________________

 

^{UPDATE 9 April 2024:  Recently a UVP member has reported that the thicknesses of filters received from Tangsinuo have not matched the requested thicknesses in the order. For example, one filter was .5 mm thinner than requested. Please INSIST when ordering that your requested thickness is supplied or else you will give Tangsinuo a bad review and file a complaint with Ebay.} 

 

See Tangsinuo Technology on Ebay for ZWB filters.

Our member Yves W. suggests the following IR-blockers for the ZWB glass. Thanks! 

QB39 is said to be equivalent to Schott BG39.

 

• ZWB1 + QB39
• ZWB2 + QB39
• ZWB3 + TSN575

 

Thicknesses: It is difficult to probably know for sure what thickness to recommend because the specs of Chinese filter glass are not quite the same as the equivalent Schott or Hoya versions. In a later discussion, 2.00 mm is the generally recommended thickness. 

 

Stack Prices: You can probably get a ZWB + IR-Blocker stack for under $100(US).
Prices depend on vendor, diameter size, thickness and current availability.
 
WARNING NOTE:  Most ZWB glass is uncoated. ZWB glass is prone to oxidation and must be regularly inspected and cleaned.
 
IR-BLOCKER NOTE:  BG39 or QB39 glass both cut UV transmission more than the recommended Schott S8612 (now hard to find), so exposures might be a bit longer.
 
WARNING NOTE:  Again, please understand that there can be quality control problems with Chinese optical glass. Striations, pits, visible leakage and/or other flaws have been noted. The currently recommended manufacturer considered reputable by several UVP members although there have been some occasional flaws.

NOTE: Refunds from Chinese vendors are usually *not* possible.

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Name-Brand Filters __________________________________________________

Update 22 May 2022:  There are currently 4 name-brand UV-pass filters for which IR leak is minimized. So you will not see any of the astro filters here which pass too much IR for our purposes. Even with these four filters, there may be shooting scenarios in which adding an IR-blocker could be helpful.

 

• AndreaU MK II  Link
  UVROptics
  $249.00(US) for 52mm.
  358BP46, 58% at peak. OD 3.7 or more from 398-1100 nm.  
  Absorptive. No violet toe. Some of the AndreaUs of past years had that violet toe (which I liked, actually). All of the AndreaUs have been good filters.

 

• KolariU Link
  Kolari Vision

$249.99(US) for 52mm.
365BP40, 50% at peak, OD 3.5 to OD 4.3. Check for current specs.
Absorptive, coated. Less expensive than BaaderU and more robustly & nicely mounted. I've used the KolariU successfully in multiple UV scenarios since it first appeared. Slightly longer outdoor exposures are sometimes needed if sunlight is not strong. Supplemental UV-flash for close work outdoors will speed things up.

 

• BaaderU Link   I don't consider this a beginner's filter!!
  Baader Planetarium
  $387.00(US) for for 2"/48mm.
  360BP60, 78% at peak, OD 4.0?

Dichroic (dielectrically coated). Schott UG11 substrate. Fast. Very expensive. Not as good on wide-angle lenses due to potential dichroic discoloration effects (which can sometimes be fixed by some tedious trickery in post). Threads are good, but mounting ring is a bit too easily bent or dinged when used for photography in the field. Some have noted minor IR leak under certain photographic conditions, so an additional IR-blocker might be useful. Sharp, sharp, sharp. I've used this filter for more than 15 years for close botanical work.

 

• UVBplus Link  Not a beginner's filter due to lens and lighting requirements!

UVROptics
$249.00(US) for 52mm. Range approx. 275-380 nm.

331BP75, 64% at peak, OD 3.2 or more (check with manufacturer).
Absorptive. You will definitely need a UV-capable lens which can cover that 331 nm peak on both sides to get the best from this filter.

Note that the UVBPlus's transmission chart indicates the possibility of about half-UVA and half-UVB light passing this filter. In Sunlight there will be more UVA. So to make the most of the UVB transmission, you will need to use UVB lighting, probably indoors in a controlled lighting environment. In either case, the filter is nicely sharp. I have not yet used it enough to know whether a stacked IR-blocker might be needed in some scenarios. 

 

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Please don't post transmission charts in this topic!!

We have them all. 
LINK to Transmission Charts

[StephanN]

Please don't post transmission charts. I have them all. I only need to go find them, OK. Thanks!!!

 

Would it be a good idea to collect all (relevant?) transmission charts into one ZIP-file and put it somewhere on UVP for people to download it?

[Andy Perrin]

I personally would never recommend the KolariU to anyone, because it seems like such potluck whether you get a good one or a bad one. Why not just get one of the other options then??

[Andrea B.]

UPDATE 21 Dec 2021:  The one-time Bad Batch at Kolari Vision is long over. All is OK now.

If you are still holding an IR-leaky Kolari UV-pass filter please contact Kolari Vision for a replacement.

 

I should contact Kolari and find out what happened. I can't remember whether we asked users who reported problems whether or not they had closed their dslr viewfinder (if indeed they were using one.) I'm leaving the KolariU on there for now -- with the warning to check with KV first -- because it is the least expensive of the UV-pass options except for Chinese glass.

 

It seems rather clear from my initial attempt to list "best beginner UV-pass filters" that about 90% of our readers are going to go with the $10.00 solution and flaws-be-d@xxed !! How could we possibly be upset with them for that when serious UV gear runs to $7000 for lenses and $250-400 for one filter? It is not easy to try out reflected ultraviolet photography on a casual basis. If somebody gets serious about it, they can always upgrade.

[Andy Perrin]

I suppose so. My mom’s philosophy of buying gadgets is to research it and buy a good product, although not necessarily the top of the line, once (if you can afford it) rather than buy a cheap version and have to replace it when it breaks or you outgrow it. I have certainly absorbed that point of view.

 

It’s really unfortunate that we lost the Omega ebay store.

[Doug A]

Thanks for doing this Andrea B. Does the Hoya U340 filter, for use with the 365nm flashlight, go on the light or the camera?

 

Thanks,

Doug A

[Andy Perrin]

On the flashlight, Doug. It’s to cut the visible light. Also that looks dated — most of us are using Nemo’s (our name for a certain nameless eBay torch) not convoys now.

[colinbm]

Why is there no mention of Baader U 2" filter, it should be on the top of the list ?

[microbat52]

Also worth noting cheapest option: chinese ZBW with BG39, just cant beat the price.

[ulf]

The Hoya U-360 2mm is a better alternative instead of UG11

"Stack Schott UG11 x 2.0 mm + Schott S8612 x 2.0 mm"

 

U-360 has its peak slightly further to the 400nm border, but still below.

Then you get slightly more saturated colours as more of the upper UVA is used.

That also leads to shorter exposure time.

It is also better suited to when using more UV-marginal lenses.

[Andrea B.]

Why is there no mention of Baader U 2" filter, it should be on the top of the list ?

 

A $350 dichroic, mirrored, thin-ringed filter is not a UV-pass filter for beginners. It has to be turned when you get it, it is easily scratched, the ring is easily bent. You need to know how to deal with dichroic discoloration and possible flare or reflection artifacts. You have to know when to add an extra IR-blocker to it.

 

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Also worth noting cheapest option: chinese ZBW with BG39, just cant beat the price.

 

ZWB1 is mentioned in the third bullet of the filter list.

 

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The Hoya U-360 2mm is a better alternative instead of UG11.

 

Well, you can get that blue leak thing with UG1 or U-360. Some like that, some don't.

But I have added the other three stack possibilities to the filter list above. I had to take a break for dinner, so the complete list probably wasn't there earlier.

 

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[Andrea B.]

Transmission Charts for Filter Stacks

These were made by Cadmium.

 

 

Transmission Chart for AndreaU Mk II

This chart was pulled from the AU website.

will be here soon

 

 

Transmission Chart for KolariU

There isn't one that I can find at Kolari Vision?

[dabateman]

My thinking is usually

1. Best camera

2. Best lens

3. Best filter

4. Best lighting

 

For a Beginner I will skip point 1, but may just say a mirrorless camera live view, as UV you can't see and live view is so nice to have.

 

Point 2 I am thinking either Canon 40mm STM f2.8 lens or Nikkor 80mm EL f5.6 lens. Full autofocus, adaptable to any mirrorless camera and not a bad field of view. Vs full manual, adaptable to any camera and with broader UV transmission.

 

Point 3 is being argued above. But for someone starting out with little money a Chinese set of BG39 and Zwb1 may not be bad and very cheap. Trade that BG39 for S8612 if you don't want any IR leakage.

 

Point 4 best light is the sun. Free, strong and gets you outside. Alternatively then a compact BLB fluorescence light bulb would be best. Its cheap, broad UV band and has same UVA intensity as many LED lights.

 

For UV induced fluorescence though, then a U340 filtered UV flashlight is best.

[Andrea B.]

We are not doing Best Lens or Best Camera here.

 

Everybody has a different opinion on those. :lol:

[diant]

Andrea, thank you! Very helpful list for a beginners.

My two pence.

 

> Schott and Hoya filter glass is uncoated and must be maintained.

 

If I right understand the words "must be maintained" (keep and handle with care etc.), UG11, U-340 and ZWB1 really need in it - these are the phosphate glasses. But UG1, U-360 and ZWB2 rather need not in any special maintaining. These are a silica glasses and chemically similar to a usual window glasses, which resist all weather conditions during a tens years without any coating. They are "self-maintained" (if so can be spoken).

 

> Stack ZWB1 x 2.0 mm + Schott S8612 x 2.0 mm Link

> $155.00 = $5.00(US) + $150.00(US), both estimated for 52 mm diameter.

 

I've followed the link and seen that the real price of 2mm ZWB1 in 52mm barrel is $14.

 

 

On the flashlight, Doug. It’s to cut the visible light. Also that looks dated — most of us are using Nemo’s (our name for a certain nameless eBay torch) not convoys now.

 

Andy, please tell me, how strong is effect of solarization of U-340 filter mounted on a 365nm flashlight?

[Andrea B.]

Yes, I should clarify the maintenance statement. Will do!

It's especially important to include any BG glass in such a statement, so I'll add that too.

 

I got the prices all screwed up in the first draft. There is some improvement on that now. I found it really difficult to locate specific sizes and thicknesses for the ZWB glass. So I just wrote that a buyer could "probably get a ZWB and IR-Blocker stack for under $50(US)".

 

спасибо for the feedback!!

[ulf]

 

The Hoya U-360 2mm is a better alternative instead of UG11.

 

Well, you can get that blue leak thing with UG1 or U-360. Some like that, some don't.

But I have added the other three stack possibilities to the filter list above. I had to take a break for dinner, so the complete list probably wasn't there earlier.

 

I do not agree at all with that statement if it refers to 2mm thick U-360.

 

The transmission of 1% just above 400nm is not visible at all.

The resulting images are very similar colour-wise to a Baader U image, without any trace of a blue leak thing.

 

There are not the same demand for high OD at the 400nm border as there are for IR leakage.

IMHO OD 2 is more than enough.

 

Cadmium is known to take any trace of blue leakage very seriously.

He too recommend U-360, 2mm stacked with S8612 as a valid "UV-only" stack

You get some blue leak with thinner U-360 and UG1, but not with 2mm.

[Andrea B.]

If I add the "Nemo" torch, then I need somebody to tell me that actual brand name and provide a link.

Thank you in advance for helping with that.

 

**********

 

I think the write-up is taking shape now. Most everything is in place. Improvements have been made from everybody's suggestions and comments.

 

**********

[ulf]

If I add the "Nemo", then I need somebody to tell me that actual brand name and provide a link.

Thank you in advance for helping with that.

 

**********

 

I think the write-up is taking shape now. Most everything is in place. Improvements have been made from everybody's suggestions and comments.

 

**********

 

Nemo is brand-less when bought from eBay

 

Would an eBay link be OK?

I find them by searching for 15W UV torch and identifying by how they look.

Nemo:

https://www.ebay.com/itm/353446705743

 

The Nemo is not a 15W torch. That is marketing BS.

 

The search containing non Nemos too.

https://www.ebay.com...ilter&_osacat=0

[microbat52]

Also worth noting cheapest option: chinese ZBW with BG39, just cant beat the price.

 

ZWB1 is mentioned in the third bullet of the filter list.

 

 

 

Sorry I mean as cheapest stack option. The zwb stack option you had was in the $100s, with the chinese BG39 you get a complete solution for $25.

[Andy Perrin]

Andy, please tell me, how strong is effect of solarization of U-340 filter mounted on a 365nm flashlight?

I have no idea what you are talking about here. Possibly lost in translation? Anyway what I meant was that you need some U glass on the flashlight to cut out any remaining visible light from the LED (of which there is a very small amount, but enough to mess up a fluorescence photo at close range.)

[diant]

I mean that UV-pass phosphate glasses irreversibly degrade under strong UV radiation. Such are UG11, UG5, U340, U330, ZWB1, ZWB3. The position of filter on a flash is a place where UV radiation reach its maximum.

 

All producers warn against strong UV radiation flow through their phosphate glasses. You can read about it here (page 25).

If UV-pass filter has strong resistance against solarization, producer usually points on it specially, like here or here.

[Andy Perrin]

Oh, I guess that is a concern in theory, but in practice, I have not observed any such effect in the time I've used my torch for. We are not shining lasers through it, and most of us only keep the torches a few years anyway before something better comes along. But even if the glass got bleached, you could just replace it?

[Andrea B.]

I mean that UV-pass phosphate glasses irreversibly degrade under strong UV radiation.

 

I think most of us know solarization under UV is a possibility, but I have not yet seen it in practice either.

 

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Torch Note

 

I find it personally difficult to list a recommendation for purchasing a random, no-name UV torch on Ebay. There is just so much scammery going on amongst UV torch vendors of those cheap torches. I will direct beginners to the forum pages for discussion of less expensive UV torch possibilities. The Convoy S2+ is a rock solid option.

 

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