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UltravioletPhotography

Nichia UV LED Lamps


colinbm

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Hello Everybody

I am looking to purchase a Nichai UV LED lamp, suitable for UV photography.

Are they available with swappable, selective UV wavelengths LED's ?

I don't know if they are available in Australia or where in the world they can be purchased ?

Cheers

Col

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Well, lots to talk about here.

Let me say up front that what you really want for photography is a dedicated UV-flash!!

 

But I'll tell you everything I know about my UV-LEDs and give you some links to look at.

 

A few brief points about using UV-LEDs for photography:

  • Using a narrowband Nichia 365 or 385 UV-Led indoors creates rather monochrome photos.
    With a well made UV-Led torch or lamp, the UV light is fairly good.
    But the light tends to cover a fairly small area if used close-up so it's easy to get hotspots.
    If used further away from the subject, you can mitigate that, but your exposures are longer.

  • Used outdoors, I've found the UV-Led light does not mix well with sunlight
    and makes 'blotchy' photos which do not respond well to editing.

  • The LED chips are not really easily "swappable" as far as I know.
    But my best UV-Led setup has three different custom tubes which can be mounted in a hotshoe holder and plugged into the battery pack.
    My custom made UV-Led torch would permit changing the front torch head (containing the UV-Led chip), but I found it kind of a pain when I was using them regularly.
    Eventually I ordered another back portion and now have two torches.

  • UV-Leds are excellent focusing aids for shining on the subject
    while focusing through Live View on a broadband camera with an external UV-Pass filter.
    They are especially useful indoor focusing aids.

****

 

Now I'll go try to find the links and will add them here to this first post.

 

Added Later:

Turns out I put all my UV-LED info into the Stickies.

(Does anyone ever read these things?? :D )

 

The first UV Sticky has my links to two Nichia UV-LED setups which I own and use.

Less powerful UV-LEDs can be found on Ebay with the usual Buyer Beware advice.

 

The UV Sticky #1: Intro, Cams, Mods, Lights, Links 2014

 

The UV Sticky #2: UV Lenses 2014

 

The UVIR Filters Sticky 2014

 

The Infrared Sticky 2014

 

Sample Outdoors Photo showing problem in mixed UV-Led and Sunlight:

stay tuned.

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Col,

 

Andrea is correct. Even the more sophisticated, commercially-available LED "torches" are not as "broadband" in their UV-A distribution, compared to modified xenon tube-based flash guns with a fuller spectral coverage.

 

We're probably talking about a typical LED chip that uses a cluster of diodes that emit within a narrow range of about 30 or 40 nm wide (at most) ... but more likely, with usable emission peaks probably more along the lines of 15 to 20 nm of bandwidth within the UV-A (given a very steep UV emission drop-off, unlike some non-LED lighting). Not a very colorful UV response, for sure.

 

However, there may be some hope with LED-based UV illumination, if working outside of commercially-assembled LED torches.

 

I just ordered several packets of industrial grade LEDS, directly manufactured at an electronics plant in Germany. And what I found was that there are now UV-emitting diodes being manufactured for industrial / textile / medical applications that have been custom-tuned to emit within specific bands of radiation (Ex: 210 - 230 nm, 245 - 265 nm, 280 - 300 nm, 315 - 335 nm, and so on). So, my line of thinking was to order several packets of UV diodes within each specialized narrow-band, and build my own lighting panel / array, by clustering all of the diodes together into one array, to create a "UV overlap" emission that would then cover a broader band. :D

 

(I also thought to order a packet of visible-band LEDS - in blue, green, and red colors, as well as "pure white" for overlap - to add to the custom-assembled array, so that it can be used to take visible and UV shots, back to back, without switching light sources, hence helping to make both photographs look identical in light distribution / shading / etc. Just like regular sunlight VIS / UV dual photography).

 

I truly believe that this will be successful. One thing that I do have experience with, is electronic component design, soldering, circuitry board building, and otherwise. I also understand basic electronics theory, so that I can make a stable power supply for this broadband LED light panel I am building from scratch. I also have the help of my father, who is a retired electronics and mechanical engineer.

 

If this proves to be as successful as I anticipate, after the assembly is complete and tests are done, then perhaps I can even start assembling more units, for sale to other UV photographers!

 

Imagine the versatility of continuous broad-spectrum lighting, indoors, without the additional heat production and lighting limitations of a momentary flash gun! The potential there is staggering! To be continued, but I will keep you all posted. I believe that I am on to a novel idea, here. A custom-built broadband LED lighting array / panel, for UV photographers!

 

(I also plan to make these broad-band lighting panels with triple power options: A DC-power input, via AC outlet ... batteries ... or car cigarette lighter.) Thus, I am planning to make it a circuitry system based on 12 volt DC (with proper voltage step-down for the typical 3.5 V forward-voltage diodes used in the array).

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Col,

I got a 365 nm LED torch from Don McLeish which works well but doesn't replace a modified flash such as the Nikon SB-14 (supplier also on Sticky). Disadvantages of LED torch, (a) it is monochromatic so you don't get the false colours as with sunlight or flash, (:D the strength of the LED appears to be (on a rough test) about the same as sunlight which can lead to subject movement with an exposure in seconds whereas flash does tend to stop movement.

 

Cheers,

 

David

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Thanks everyone for the help, much appreciated :D

What I want to do is use the 365nm led as a calibrated UV light source, to see what my camera & lenses can 'see'.

I guess the big picture is to have a number of narrow band UV LEDs that I can use to calibrate & test the useful responses of camera & lens.

Yes Dave, a Nikon SB-14 UV capable flash is on the short list. First I have to get a setup (camera & lens) that can use it :D

Cheers

Col

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David & Col,

 

Speaking of modified flash guns ... there are more financially feasible alternatives to the more expensive Nikon guns. Even easier to modify, than the Vivitar 283 / 285 series.

 

In fact, there is one lesser known ("hidden gem") flash unit, which takes all but a few minutes to modify into a fully-functional, broad-spectrum flash gun that can compete with the best of them, for a mere fraction of the cost.

 

I am referring to the Metz Mecablitz 45 CT-1, as one of the best alternatives out there, with no financial burden or risk to life and limb, for any dangerous modifications.

 

The main advantages are:

 

1. The Metz Mecablitz 45 CT-1 has more powerful UV output ("UV brightness"), per charge / flash, compared to the Vivitar 283 / 285 flash series. This will, of course, mean that one requires LESS exposure time to obtain the same results (or, less sequential flashing, per photo, to "build" enough UV strength / output).

 

2. The Metz Mecablitz 45 CT-1 is much easier to modify! In fact, it does not need to be disassembled in any way, to remove the fresnel plastic! The flesnel can be taken off, with some force (and a sharp knife jammed under the plastic edges). This is because the construction of the Metz gun has accessible joints between the fresnel lens and the housing, where one can grab hold of and pop the fresnel right off, without damaging the housing of the flashgun. This means less than 1 minute, to make an instantly usable UV gun! No risk of damage from disassembly! And no time lost in modification! Because disassembly is not necessary.

 

3. Any replacement clear Schott glass (for protection of xenon flash tube) can also be glued directly onto the same corners where the previous fresnel lens occupied, all without disassembly. Another easy job, within mere minutes of invested time.

 

4. The xenon flash / firing tube inside the Metz 45 CT-1 is completely bare and uncoated! No treatment is needed! It has superior, out-of-the-box broadband response, all without the expensive alternative of going with the over-praised and over-hyped Nikon flash guns that can cost $$$ more!

 

5. The Metz 45 CT-1 can be had for about $30 to $70, USD, on Ebay! Depending on seller / auction. Dirt-cheap, next to the other options.

 

(You do not need to go for any offers with the added accessories, cords, cables, or parts. They are not mandatory! Just get the flash unit, itself, listed as in "working" condition.)

 

 

Thus: For UV photographers on a budget, and wishing a very usable and competitive alternative, I recommend you get yourself a Metz Mecablitz 45 CT-1, and try it yourself. You won't be disappointed.

 

 

NOTE: The only downside to these flashguns is that they have a VERY HIGH trigger voltage, and so, must be used hand-held / off of the hot-shoe (which I prefer, anyway ... since I like to do multiple flashing per exposure, and "fill" the photo evenly with light by "flash painting" from multiple angles, to eliminate harsh shadows and unevenly lit subjects).

 

The second downside (and this is very minor), is that you have to buy an aftermarket battery holder / battery pack (for housing 6 AA batteries), because all of the original rechargeable battery packs that were once sold with this vintage unit are no longer chargeable. They have lost their ability to hold a charge (they are sealed, proprietary battery packs).

 

But, these aftermarket battery holders are dirt-cheap as well ($10 for one, or $25 for a three-pack, if you want to have more than one battery pack on hand, for extended work).

 

Here is a link for one trusted Ebay seller (from which I got my own battery holders), as an example of one pack:

 

Item # 161236938021

 

And here is a three-pack sale:

 

Item # 160996753021

 

You can see, these are quite cheap, and plentiful.

 

Anyway, it depends on one's preference. If you want sufficiently usable (and dare I say, outstanding) UV output ... and you prefer to shoot hand-held / off-camera like me (which allows me to do multiple flashing of my subject from different angles, to get more even lighting during a long exposure) ... then the Metz 45 CT-1 is a much more easier-to-modify alternative to the Vivitar 283 / 285 series (while still being within a cheap, accessable price-range). And, in terms of price-per-output performance value, it is far superior to just about any other flash gun out there, bar none.

 

It's certainly a VERY EASY conversion, requiring no more than a minute to pop off the fresnel lens, without any disassembly or tinkering of internal parts. And, just a few minutes more, to glue on a clear protective window, if you choose to do so.

 

(When I first bought my own Metz 45 CT-1, I had it ready for indoor UV photos just 5 minutes after unpacking my Ebay package delivery. :D)

 

To heck with the Nikon UV flash purists on the 'Bay, pumping up the prices. Haha. They can make others blow their wad of cash, if they like burning money for nothing. I prefer to keep my cash, and still get good results. :D

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By the way, here are samples of shots taken with the Metz Mecablitz 45 CT-1. The flower subject is Bubline frutescens.

 

Also, the third photo is just a brief collage of my "makeshift" home set-up, on a shoestring. Notice I use the "helping hands" tool (originally designed for those working with soldering circuit boards), as a way to clip my flower in place, and also articulate the precise position that I want to photograph it in.

 

The "helping hands" soldering tool is a great way to keep the subject stable, and it allows full "pose-ability", rotating the gripper arm in any direction you desire. It's cheap, too (about $10, USD, or so).

 

Item # 200776287211 (on Ebay), as an example.

post-34-0-85624700-1395290564_thumb.png

post-34-0-47365900-1395290576_thumb.png

post-34-0-47604500-1395290691_thumb.png

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Thank you, as well!

 

Isn't this website truly shaping up to be a great resource for sharing ideas?! This is just awesome!

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The thing about a mixed UV-LED panel is that the LED beams don't spread much so the light doesn't blend into a broader UV spectrum.

I've had trouble blending my various UV-LED torches. You get one central spot that is blended, but away from that things get blotchy.

I guess you all can tell I'm not much enamoured of UV-LED so far. "-)

 

*****

 

Col, it might accomplish the same testing goal and be easier if you just get some Thorlabs narrow UV bandpass filters and shoot with those?

I've been on the point of ordering those about 5 times, but every time something else comes up to spend the money on.

(Like the current broken dental filling. Sigh.)

It seems like if you want to try UV-LED torches for figuring out what your lenses and cameras can see, then you might have to make your own!?!? The retail selection is somewhat limited it seems. Back when I got my UV-LED kit and torches, Nichia was the only one making strong (powerful? not sure how to say that?) UV-LEDs and only 365nm and 385nm were available. I'm sure things have changed since then from industrial sources. But the Ebay/Amazon offerings don't seem to have changed much.

 

Another possible light source - I have this $15 "sanitizing" wand at 250nm (I think. Need to verify that.) It is very weak - and **very** dangerous to your eyes so it has a top cover. I set up in a dark room, but had a terrible time getting a good photo. Interestingly I got a chunk of Calcite to phosphoresce with it. That was cool to see. But no way to photograph it because it was such a short interval. And too dark.

Before someone corrects me, I do not mean fluoresce. I do mean phosphoresce. "-)

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Thanks Andrea

I have thought about Stephen Smeed's "Sparticle Bandpass Filter" setup, which uses a range of narrow band filters.

The filters are not cheap at about USD135 each, but you still need a light source to cover each filter.

The LED's are cheaper & are their own light source, with the application of the correct power supply.

It is interesting though to see the different wavelength responses of the Bayer CFA cameras.

Down near the bottom of this page

http://www.dyxum.com/dforum/can-sony-minolta-dslr-be-used-for-reflected-uv_topic69441_page3.html

 

http://images.nikonians.org/galleries/data/22542/medium/Kuribayashi_35_UV_transmission.jpg

 

Cheers

Col

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Col, I think the guys using these are just using them in strong sunlight. No one I know has light sources for them.

 

I really like your idea of the UV Leds over a wide range.

But last time I sourced Uv Leds, I found they were a bit pricey, too.

We do not have an inexpensive hobby!!

 

BTW, I looked at the link where Alex discusses Sony cams for UV, but I did not see any response curves?? (It was an informative, interesting discussion.)

 

Note to Self: Add info about Sony conversions to Sticky. (Pellicle not good.)

 

Igor, you are without a doubt the most enthusiastic poster we've ever seen in our tiny little UV world!!!

If I don't already have that Metz listed in the Sticky, I certainly will do so and thank you.

Duuuude, you could do *Info-mercials* or write ad copy as an alternate career path to whatever your current day job is!!! You are fun. [Just keep it factual and referenced, too.] "-) "-) "-)

 

Note to Self: Add Metz to Sticky.

 

Andrea's Choice of the Day:

Fix broken filling

OR

Order Thorlabs narrowband UV pass filters and fittings

OR

Order Nikon new 80-400VR ???????

Hmmmmm, what will she do?

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Thanks Andrea

Glad you found the link useful.........something else for you to cut your teeth on :D

Most LED's are cheap for VIS & IR but further into UV the price rises & they grow another leg, three instead of two.

I will have to find out how these three legged LED's are wired up ?

As Iggy said it is pretty easy to wire up a board with a range of LED's to a battery to display a range of wavelengths.

I have seen 365nm LED's with two legs, but shorter wavelengths, I'll have to see what Iggy has or knows ?

I guess I could hope to find a couple of LED's around 320 & 340nm or so, that should cover anything I am likely to need to pass UV for photography with the available Baader or Andrea UV filters.

Cheers

Col

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And, Col, if you do get anything working, please photograph it and write it up for us !!!!

 

Repeat: I didn't see any Sony response curves? Did I miss something?

 

There's another thing to spend my $$ on -- I need a broadband Sony for its flange focal distance for a couple of my lenses so they will focus to infinity. My current obsession: focusing UV lenses to infinity. I shot close-up for about the first 4 years of this adventure. Of course the UV-Nikkor will shoot to infinity. But I wanted a wide. Of course the Novoflex will do that. But I wanted other focal lengths. And.so.it.goes. Too many lenses, not enough time to shoot with them all.

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Sure will Andrea, as always into sharing.

Hopefully Alex will come to the rescue with some Sony data for you too.

Col

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Doesn't anyone still use the UVP Model B-100? I have two and find them quite handy. Of course, they are only for indoor work, unless you have a generator with you.

 

I prefer to use mine without the Wood's filter (about 12mm thick), as the filter gives me only 365nm. Sans filter, I can take Vis, NIR, and broad range UV. Mind you, these mercury HID are briggght and care should be taken. See http://www.uvp.com/pdf/Pen-RayLampSpectra.pdf

 

Older models are sometimes available on ebay. I bought one for $65.00 USD.

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Repeat: I didn't see any Sony response curves? Did I miss something?

 

What curves do you want me to provide, Andrea? The ONLY sensor responce curve that I know about is published for Nikon D80/D200 sensor (similar to Sony A100 sensor but not identical) by Klaus Schmitt here: http://photographyoftheinvisibleworld.blogspot.se/2009/08/nikon-d80-d200-spectral-response-uv-ir.html

 

I do not have tools to provide such data as Klaus did in his post. In the link provided by Colin I only tested average UV sensitivity of unmodified Sony cameras comparing to Nikon D70. Nothing more.

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Perhaps the histograms in the Sony post were misinterpreted? No matter. Let's let this one go. I simply thought I had missed something in a lengthy post.

 

*****

 

Reed, those Blak-Ray lamps look interesting. Did you replace the Wood's filter with a clear broadband glass??

Specs say they can cover a 5 inch area at a 1.5foot distance. That would certainly be quite useful for floral UV signatures.

 

UVP offers some very interesting UV application links. I'm going to go read through some of those straight away.

LINK: http://www.uvp.com/appnotesuv.html

 

*****

 

Alex, I raised the quote limit to 5. It was never set. Too high and server can get stalled, so we will try 5 initially.

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Perhaps the histograms in the Sony post were misinterpreted? No matter. Let's let this one go. I simply thought I had missed something in a lengthy post.

 

Andrea, those histograms were just used to provide a bit more information about the exposure data for each shot - exposure and ISO. That is why the pictures are gray-scale and the histograms are also based on grey-scale shots. I did not want to speculate about anything I am not able to measure. I am experimenting with never Sony sensors right now, and, although I do not have precise measuring equipment, I can and will do some comparative tests with narrow-band filters in the nearest future. I'll post it separately on UVP.

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Newer Sony sensor tests would be very useful Alex.

We were all so Nikon oriented intially that I haven't had much info about other cameras.

 

I will try also to do some kind of comparative test with the Pentax K5 - eventually.

 

Why must integrating spheres be so expensive? (Rhetorical question.)

 

BTW, what narrowband UV-Pass filters do you have?

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I most commonly use 325BP10, but have three more, with peaks of around 280, 340 and 365 nm. I have to check for exact specifications.
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I've never been able to get much at all with my 292BP10. Used it on a D300, I think it was. Most likely I hit a sensor limitation, but don't know for sure. However, I should repeat that test with the D600 and K5, just for grins.

 

How about your 280 ???

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The Pentax K-5 is thought (by dpreviews) to have the same sensor as the Nikon D7000, and the K-3 equivalent to the D7100, I think they were thought to be Sony sensors.
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