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[UV SAFETY] UV-C Light Is Dangerous NEVER look at a UV-C light. NEVER let UV-C light hit your skin or eyes directly or by reflection. UV-C light can cause: severe burns of the eyes and the skin, and DNA damage from broken chromosomes. When working with UV-C illumination, you MUST: cover up completely, wear head & eye protection, and have strong ventilation. While working to determine why my CuRB didn't reach into the UVC (I have determined that my old CuSO4 salts are contaminated), I decided to create a liquid filter for UVC use in solar-blind applications. I have named it the MaximumC. The MaximumC chart is below: For those who want to eliminate the Vis and most of the NIR, but still retain much of the UVC, here is the MaximumC stacked with a ZWB1, 2mm thickness: Regards, Reed

Does this image show that the ZWB2 filter that I bought from Tangsinuo has excessive striations? It was taken with EF 40mm f/2.8 STM, ZWB2, and BG39. I can reliably reproduce such striations with this filter. However, the bokeh from the ZWB1 filter that came with Igoriginal 35mm f/3.5 is always smooth. So I suspect that the Tangsinuo filter is defective.

Ok, a very preliminary test (in the 5 mins between getting home and the sun going in). I recently got a 308nm band pass filter on loan from Invisible Vision in the UK (http://www.invisible...ts/accessories/). This filter is not aimed at skin imaging, but used for monitoring combustion processes, and the chap at Invisible Imaging said he'd never heard of anyone using it for skin imaging. Given I have the UV-Vis-IR Eos 5DSR, I did a comparison of this 308nm filter and the Baader U - just to see whether I could see anything with it, to be honest. I started with a quick transmission measurement - both filters, on UV Vis at work. I ran them on a Perkin Elmer Lambda 650S UV-Vis spectrometer (150mm integrating sphere) to measure transmission between 250nm and 800nm (1s collection time per nm). The graphs are shown below. Quick photos of my lovely and long suffering wife. She was wearing some sunscreen on her face at the time, and the photos were done about 4:30PM in direct sunshine, facing the sun. Firstly, with the Baader U. ISO 800, f8, 1/10th second exposure. Image has not been modified since coming from the camera as a JPEG. Focus not brilliant I accept, but I had limited time to optimise everything before the sun went in. Second picture, with the Invisible Vision 308nm filter. Very different settings, ISO800, f8, 1.3 seconds. To be honest this was further tweaked in Photoshop, and I think the actual exposure to get this brightness would have been nearer 2 or perhaps even 3 seconds. So about 4 stops different to the Baader U. For imaging these lower down wavelengths I wasn't sure what to expect, although I thought I'd see similar to the Baader U image but perhaps with more contrast. However I'm wondering here whether I am seeing a product of very little sensor sensitivity at these low wavelengths, at which I am starting to pickup contamination from other wavelengths (the Invisible Vision filter is classified as OD4). Perhaps if I'm being optimistic the sunscreen looks darker through the 308nm filter than the Baader U, but I think it's far to early to be certain of that. The camera sensor is covered by a WG280 Schott glass, so even the transmission of that is starting to tail off at these low wavelengths. Has anyone done photography of people at these low wavelengths, or know what to expect?

Hi, I'm 100% sure that when I was buying CuRB filter (https://www.uvroptics.com/index.php?CuRB) its chart was showing transmission down to 200 or 210 nm and it had about 20% at 222nm - I was so xited with this filter suggested it in many places. Now I see a new chart dropping to 0 at 300nm - is this a bug on UVR optics site? If I bought filter when its transmission was down to 200nm and now it is zero at 300nm - what will I receive? Anybody (by any chance) have screenshot of old transmissin curves for CuRB & CopperU? I want to have them, so in case when my filter is cutting at 300nm I can get refund. Even now the description on website says "As well, the fused quartz reaches farther into the UV, not dropping below 90% transmission until 270nm" - which means that I have 90%transmission at 270nm, not 0 below 300nm... what is the true transmission? Can I have a very detailed transmission curve (with OD values, not just %s) for CuRB & CopperU. I bought this filter to block IR and pass UV-C - this is THE MAIN reason I bought it. EDIT: I can also see CopperU chart now on the website, it drops to 0 around 260nm and it uses CuRB internally, so new chart for CuRB must be wrong, right? Correct me if I'm wrong? https://www.uvroptics.com/index.php?CopperU cc @rfcurry

In yesterday's article, MING dealt with the topic of "streaks" in optical filters and asked about their detection/visualization. LINK ULF referred to a corresponding article by SCHOTT. Shadowgraphy is presented there as a simple and rapid method for visualizing striae (variations in the refractive index in an otherwise homogeneous medium). Today I looked to see whether shadowgrapy (without having to make optically demanding setups) could also be suitable for us to assess the quality of our UV filters. The result is encouraging, I think. A PTFE plate has proven to be a suitable screen. However, it should be fresh and finely ground to ensure a homogeneous background. My plate was too rough and shows too many structures. You can of course take a reference image and subtract it from the measurement image. But that doesn't make things easier. Setup: 3 W LED 365 nm as light source, 4 m distance to the projection surface, PTFE plate. Canon 6D-FS with EF 2.8 90mm TS-E and ZWB2 filter. Camera-screen distance 2 m. Distance of the examined filters to the screen also 2 m. Everything reasonably coaxial (camera slightly offset, compensation by shift lens). The resolution can be improved by reducing the relative size of the light source (i.e. either a greater distance from the screen or a lens hood in front of the lamp). Of course, this also reduces the amount of light. White balance and focus on the screen. Aperture 2.8, 1/8s, 3200ASA. To check the sensitivity, I recorded butane gas escaping from a lighter and a butane gas flame. I examined three filters as objects: ZWB2, QB21 and a laboratory cobalt glass (mounted as a round filter). The two optical filters show no streaks or other optical defects, the laboratory glass clearly shows them. Finally, a picture of float glass (glass of a picture frame), which visually appeared completely homogeneous and absolutely flat. Light source: VIS LED. Diemensions according to the UV stup, but with a 1mm pinhole. Rotation of the glass plate. Result: The optical density of this float glass is very inhomogeneous! The method can certainly be fine-tuned and the "Bokeh striation method" of MING seems to be a lot more sensitive. But the shaowgraphy is quickly set up and surprisingly good for a first qualitative evaluation! Maybe someone will do comparative tests on it...

At the moment Tangsinuo is selling AR coated QB21. They seem to have two different batches of this glass. From the transmission spectrum and the green "shine" one of them seems to be multicoated. The other is possibly single coated. The multicoated one transmits a bit more in the blue/UV-A than Schott's BG38 while the single coated one has a spectrum almost identical to it. My full spectrum converted E-M1 seems to give almost perfect white balance in auto white balance with what I guess is the multicoated type (I haven't yet tried the one I think is single coated, as I have it only in a very small size). The main selling point is the protection from oxidation afforded by the coating, but nevertheless it should also help with flare and ghosting. I show here the spectra I measured (without an integrating sphere).

I recently had one of my Canon EOS 5DSR cameras converted to multispectral by MaxMax. When Dan did this I asked him to send me back the internal filters which he removed from the sensor, as I wanted to measure their transmission spectra. This post is a quick writeup of what I found. Transmission measurements were done using an Ocean Optics FX spectrometer (between 250nm and 800nm), and an Ocean Optics DH-2000-BL light source. Internal filters Two filters were returned along with the camera - a clear one and a green one. The clear one is apparently the coated ICF assembly and dust shaker, and the green on is BG38 or something similar to block IR. I noticed that the clear one started to look green if I held it an angle, and wasn't looking straight on at it. At certain angles it had a red tinge as well. Pictures below show the two filters. Firstly the green IR filter (these often crack during removal as they are stuck onto the sensor and are very thin). And the clear ICF filter assembly, showing the colour effects at different angles. Transmission properties The first set of plots shows the transmission of the two filters individually, and when combined together. This was done with the light source at 90 degree to the surface of the filters; As expected the green filter shows the typical IR filter profile. The ICF filter looks to be a UV/IR cut filter. Combined together they give a strong UV and IR blocking (apart from a weird little spike around 370nm), and strong red attenuation. The second graph, shows the transmission through the ICF filter, when the filter is held at different angles, from flat (incoming light at 90 degrees) up to 60 degrees from flat (incoming light at 90 degrees to the filter surface); The graph is a little busy (I can split these out if people are interested), but shows as the filter is tilted angle of the incoming light moves away normal to the surface, the transmission characteristics of the filter vary quite significantly. With increasing angle, the transmission of the filter shifts to the left, to shorter wavelengths, with less red being transmitted. This presumably while it looks green when looked through at an angle. It also gets pretty complex, with certain wavelengths being let through and others being blocked. The red seen on the filter at certain angles is presumably reflection (I'm guessing as it isn't being transmitted, it is being reflected). It needs to be tilted quite a way to get these shifts, but it does make me wonder what is happening with, for instance, extreme wide angle lenses - what is the most extreme angle the light can hit the sensor from the back of the lens? Could this lead to colour shifts towards the edges of the image? Do the effects become more extreme with mirrorless cameras where rear lens elements can get much closer to the sensor?

I'm using the Tiffen UV haze 2A that cuts off at about 410nm. The 2E cuts off at about 385. Would the 2E improve results shooting UVIVF with the Nemo 365 torch and a stock camera? On daylight preset my images are slightly bluish with the 2A. Would the 2E reduce this? Wouldn't it make even more difference with electronic flash? Thanks, Doug A

If you read my previous post, you might have seen me talking about the fact that my ZWB1 has developed spots that won't go away even after I soaked it for days in hydrogen peroxide. I wanted to see if I could possibly fix it by scrubbing it with Cerium oxide instead, but I don't really know how it works. I'm sorry if there is a tutorial on here somewhere, in that case can someone please just direct me to it? I'd like to know about the toxicity of cerium Oxide and about the general risks of scrubbing the top layer of the exotic glass substrate. I'd like to know how to scrub the filter correctly, also if someone could tell me where one can generally buy Cerium oxide (links appreciated). Thanks.

https://www.ebay.com/itm/265176732933 It looks pretty beaten up but the seller doesn't mention any damage to the filter itself. Really cheap too. I am currently saving for some more Tangsinuo glass so I won't be buying it but I figured some of you may be interested. Cheers.

Hi All, I've taken a look at my Kolari UV bandpass filter today and noticed some discolouration. Shown at the top perimeter of the filter in the attached image. I am wondering whether this is normal oxidization, user error or manufacturing issue? The discolouration is visible from the rear (lens side) of the filter but not the front and it looks like it is below the rear surface of the filter. i.e. under a laminated layer. I am happy to take responsibility if it is user error, I just need some information on what actually is going on here. To me it looks like delaminating layers. Please excuse the dust . Mat

Fog has been rolling in and out all day over Somes Sound. So I thought it would be a good time to test again the properties of basic Visible, IR and UV filters. The scene was not chosen for compositional effect (obviously), but rather for its fog and distance and inclusion of water, trees and sky. The results of a fog & distance shoot like this are always interesting. In this array of photos, we can see clearly that the longer IR wavelengths penetrate the fog much better than the shorter UV wavelengths. No surprise there. However, I'm not sure I have worded this correctly. Should we instead say that the shorter UV wavelengths are more scattered than the longer IR wavelengths? Weigh in on this, please! More detail is revealed in the IR photo than in the Visible or UV photos all of which have lots of details obscured by the fog -- especially the UV shots. This is all the reverse of the results obtained when I'm shooting floral close-ups indoors. Those flash-lit flower close-ups typically reveal immense surface detail in the UV with the IR being the softest and least detailed and the Visible in between the UV/IR extremes. The fog was constantly shifting so different areas are obscured in each frame. White balance was set in-camera for each filter. Conversion was made in Photo Ninja using a Pentax K5 profile which preserved that white balance. A bit of sharpening was added, but no other edits were made because I wanted to present basic results for the sake of comparison. ((Were I to display these photos as finished photographs, I would have made some curve tweaks and perhaps have opened up a shadow or two.)) Well flapdoodle. I see some dust bunnies or spots of something. I just cleaned that K5!! Equipment [Pentax K5-conversion + Asahi Ultra-Achromatic-Takumar 85/4.5] Infrared [f/11 for 1/15" @ ISO-80, Aperture Mode EV+0.0, Schott 830nm IR-Longpass Filter] So much more of the wave action is revealed in this IR frame. Is that because we are seeing underneath the water surface a bit? Visible [f/11 for 1/200" @ ISO-80, Aperture Mode EV+0.7, Baader UVIR-Cut Filter] Ultraviolet [f/11 for 1" @ ISO-80, Aperture Mode EV+1.0, BaaderU UV-Pass Filter] The dark dots in the water are lobster buoys or mooring floats. Ultraviolet [f/11 for 1.3" @ ISO-80, Aperture Mode EV+1.0, StraightEdgeU UV-Pass Filter]

Jason / Tangsinuo / China filters have arrived with a very expensive Fedex flight and very expensive customs fees photographic lens: Meritar 50mm f2.9 at f: 8 light: Elinchrome flash uncoated transparent tube 1500W (for VIS photo -7 stops) I'm surprised with the results the QB39 - 1.5 thick doesn't block the red - IR it is likely that the contamination of red and IR, it is because I left the modeling light on (artificial light ~ 200W) the TSN575 filter he recommended seems to work fine as a QB39 / S8612 (which I don't have) These are the results with ZWB1 and ZWB2 the last photo is with BG18 (jena glass) + black glass of the Nemo flashlight Thanks for the comments Antonio P.S. The IKEA cap is lined with Teflon plumbing tape My studio wall is a good photographic neutral gray The ridiculous molar-shaped vessel (Flying Tiger Copenhagen shop) is my dentist's idea

Hi, is there aybody who can help me ordering ANY filter down UV-B in 52mm thread? I've asked (I think) all companies listed in this forum... I need filter for UV-B or (better) UV-C. I've given them 4+ weeks to answew. I can pay 1000+ EUR for filter. Anybody can help?

Thinking about converting a small camera to full spectrum. Camera can be converted without disassembly. If I don't replace the UV/IR filter in front of the sensor, the native camera lenses won't focus to infinity. The lenses probably don't work well with UV, but it would be nice to use them with IR. The original glass is .6mm x 12.6mm x 13.1 mm. Where can I order a glass sensor cover that doesn't impede UV light? Thanks, Doug A

Today I want to share how I occasionally create blue sky IR images. Strictly speaking, these are UV-IR images. I use a ZWB2 as a filter. It has a transmission maximum in the IR around 750 nm. I do the white balance against PTFE. IR is then usually rendered color-neutral, UV violet. The IR portion can occasionally appear greenish or yellowish when the UV portion is very high. According to my observations, influencing factors are: ratio of IR to UV in light (position of the sun, degree of cloud cover); greater sensor sensitivity to IR (broader wavelength range); UV transmittance of the lens ("UV-reach"). In landscape photography, the IR intensity is usually so high everywhere in the image that the IR image practically dominates. Wood effect and haze penetration are as usual. Only the blue sky and reflections of the blue sky on water are so IR poor and so UV rich that they appear violet. I can then either shift the violet to sky blue - depending on my taste or the subject of the picture - or, in the case of a BW conversion, darken it with a yellow filter. Attached are three sample images for illustration.

Hi, I was googling a bit and I can't find... So I was always buying UV/IR filters from a member of this forum but it seems like he no longer sells filters or anything... I just need a handy IR blocker in a standard 52mm thread - anybody knows where can I order it, say 2-3mm thick? Can't find any on ebay etc. If not S8612, then what is another very good alternative to it? I need to block IR or even slightly visible, say from 650-680nm with at least OD4.5 - better OD5? And if there is any filter that does the samy but from anywhere starting at even 420nm (and keeping OD >= 4.5 until 1200nm) then what is it? Also I don't want to create a separate ticket for this, so I'll just ask here: is there any Nikon-F -> GFX adapter that also includes macro helicoid? FDD difference is almost 20mm, so there certainly is space for putting a small helicoid that would allow extra extension for even that 20mm ... same situation - googled, searched on ebay - found nothing - I'm able to find adapters with macro/helicod for GFX but from other systems (with longer FDD) like P67, P645...

Instead of cutting out certain ranges, is there a way to equalize the 3? In other words, reducing vis and IR to the same brightness as UV. Most filters cut out parts of the spectrum. Are there specific range neutral density filters? Thanks, Doug A

[UV SAFETY] UV-C Light Is Dangerous NEVER look at a UV-C light. NEVER let UV-C light hit your skin or eyes directly or by reflection. UV-C light can cause: severe burns of the eyes and the skin, and DNA damage from broken chromosomes. When working with UV-C illumination, you MUST: cover up completely, wear head & eye protection, and have strong ventilation. I have investigated & invested in a Safer UVC, Excimer 222nm Lamp, with Filter. The filter is essentially clear but blocks the nasty UVC of 254nm up to around 300nm, but unfortunately has a leak from 300nm into near IR, peaking at 450nm. First photo is of the gear. Second photo is the output from 250nm to 850nm. Third photo shows the blocking of the dangerous UVC 250-300nm.

Hi all, here are some tests with my A7r Full Spectrum and some filters (all pictures just set WB to the asphalt): I am thinking about getting the Kolari UV one. I currently have S8612 and Hoya U-360 and U-330 from UVIR Optics but I am always lazy (as you can see I didn't got them this day to shoot) since they are both 52mm and I use 58mm for everything else... So, please, critics on those pictures (and how to process them properly) and is it good or redundant for me to get the Kolari UV one? Thanks all!!! 4486: Kolari IR Chrome 4488: Kolari Hot Mirror (old one) 4490: Hoya R72 4492: Hoya Orange O(G) 4494: No filter (full spectrum)

I need a filter that passes below 320nm and blocks > 320 nm (or stack) with 52mm thread. Is there anything reccomended?

I tried the new filters from Tangsinuo with different combinations, I realized that graphs are one thing ... a practical test is much better. I tested the compatible lenses with my Sony A7 full specrtum, with a combination of Jason's new TSN575 + ZWB1 filter ... these are the results. The first two photos are with L. Meritar 50mm f2.9 Flash light 40Watt - 1/125 "- f: 16 - 50iso - QB39 (~ BG39) Flash light 1000Watt - 1/125 "- f: 16 - 1600iso - TSN575 + ZWB1 (the last photo is without UV + VIS + IR filters) then you will have to find out the numbers of ... Leitz Elmar 50mm f: 3.5 (collapsible of my old Leica IIIF) Helios 44-2 58mm f: 2 Nikkor-H 24mm f: 3.5 Nikkor-H 50mm f: 2 Nikkor-D 50mm f: 1.8 Nikkor-D 60mm f: 2.8 (micro) Asahi Super takumar 35mm f: 3.5 Asahi Pentax SMC 35mm f: 2 Asahi Pentax SMC 85mm f: 1.8 I have no photographic lens measuring tools Please ... i await your considerations. Thanks Antonio

I thought I would run a filter series with the full spectrum S1R using several filters I have. I would show both the raw colors and the white balanced version. For a similar series, here is one I did with the Pentax K5 full spectrum conversion: LINK Suggestions welcomed! Subject: standards + color checker card + flower UV-Pass: with Names AndreaU Mk1 (discontinued) BaaderU CopperU (discontinued) IonicU (on order) KolariU La La U (still made?) Luv U II (still made?) Moon Uva Miami (discontinued) StraightEdgeU Red (discontinued) UV-Pass: Dual Bandpass and Stacked Shoot the filter both unblocked and blocked with IR-blocker. UG1, UG2a, UG5, UG11 UG-330, UG-340, UG-360 Other B+W 099 (longpass) Hoya B-410 (dual bandpass) Hrommagicus Schott BG3 (dual bandpass) Schott VG9 Infrared There are a lot. So I'll pick some with color and some without. Schott RG610 Schott RG665 Schott RG695 Schott RG715 B+W 092 Hoya R72 B+W 093 Schott RG830 Schott RG1000

Hello, for quite some time, I've been looking for a filter that would let me carry out UVIVF photography without pollution by either reflected UV or the UV blocking filter fluorescing. I found this interesting offer. https://www.ebay.com/itm/164901638716?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=3YEJMsjgRga&sssrc=2349624&ssuid=aowhe3ctqce&var=464412556219&widget_ver=artemis&media=COPY Does anyone know how well does it actually block UV and if it fluoresces at all? Thanks.

UV color is a complex and controversial topic. For example, Andrea will always remind you that UV false color is not strictly related to wavelength, as it depends on many factors (lighting spectrum, lens transmission, filter transmission, sensor response, white balance...), although we always see the same colors in our UV photos: blues, lavenders/purples, yellows, and sometimes green. Red is not a color that we would expect. A different way of thinking at color outside the visible spectrum in general is to make a TriColour/trichrome/tri-band image, which often produces more natural-looking colors (for example, the sky is still blue) and also there is a wavelength-color relationship. UVP member Bernard Foot has experimented with the technique some years ago, and I have already tried it before. Other people (notably UVP member OlDoinyo) like to render white-balanced UV photos in BGR (swapping the red and blue channels), which also produces blue skies and a different color palette. Since I have a color camera, the images I take when making a TriColour image have colors, which I normally get rid of to make the channels. If I stack those images instead, I can simulate the raw image taken by a camera with an approximately flat response between about 310 nm and 400 nm, and with sunlight having a uniform spectrum too. This never happens in real life, even with a UV-dedicated lens. The interesting part is comparing the resulting colors with those of a normal UV photo. The equipment I used is the usual one: full-spectrum Canon EOS M, SvBony 0.5x focal reducer lens and the following filters: TriColour: Blue channel: double 310 nm Chinese bandpass filter + ZWB1 (2*2 mm) (the ZWB1's are not necessary, but I used them anyway); Green channel: BrightLine 340/26 filter + ZWB1 (2*2 mm); Red channel: BrightLine 387/11 filter + Chinese BG39 (2 mm); Standard UV: ZWB2(2 mm) + Chinese BG39 (2 mm); Visible reference: Chinese BG39 (2 mm); The technique used to make the TriColour images is also the usual one, described here. The major difference is that I took multiple 310 nm exposures this time and stacked them taking the darkest pixels (5 in both cases). As for the raw color stacks, I set the brightness of each image to be about the same by eye and stacked them. Also, following Andy's advice last time, I raised the brightness of my images and the contrast in the TriColour stacks (also because the contrast in the original channels was removed in PhotoNinja during the processing). The visible and UV references are white-balanced in-camera, the raw stacks were white-balanced in PhotoNinja. I used both UV-lavender and UV-yellow subjects. For the lavender, I picked three items with varying degrees of lavender: a magnifying glass on the left (transparent at 387 nm, mostly transparent at 340 nm and opaque at 310 nm), almost colorless; a white LED lightbulb in the middle, and a plastic lens on the right (mostly transparent at 387 nm but opaque at 340 nm and below, which shows a strong blue-purple color). Visible reference: Standard UV: White-balanced raw UV stack: As you can see, the color palette didn't change much, but since here the shorter UV wavelengths contribute much more to the image, the magnifying glass is noticeably darker. In general, objects with a pale lavender color got a color boost. UV TriColour: Here the color palette is obviously richer, with the color giving a good indication of the transmitted/reflected wavelengths. Standard UV, BGR: Compared to the TriColour rendition above, only the plastic lens on the right looks similar, while the color deviates more for items with a flatter UV response. For comparison, here's the raw stack, in BGR version: ...and now for the yellows. Here I used a 3 mm thick ZWB1 filter on the left, and a 2 mm thick ZWB2 filter on the right. Visible reference: Standard UV: Here the colors look similar, with the ZWB1 filter being slightly greener, as expected. Also the paper tissue I used apparently contains UV-absorbing fibers. White-balanced raw UV stack: Here things get weird. The ZWB1 filter got orange, which is a bit different from its normal color. Also, and this was expected, the difference in color (hence transmission) between the filters is more evident now. UV TriColour: Standard UV, BGR: UV stack, BGR: Raw or .tif files are available.