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I have been thinking about this for a while. Although modern lenses rarely have a good UV reach (350 nm or so), they are easy to buy and if still manufactured, you can buy them new. You don't have to rely on good surviving copies available in a limited amount. While testing for infrared capability has been done much more systematically, this is not the case for UV. The reason is probably the more diffuse practice of infrared photography compared to ultraviolet photography. The latter is still quite niche and not very well known. A lens that has good UV and IR performance is good for general-purpose UV/VIS/IR photography. The 350-400 nm range is fine for normal UV photography, for showing nectar guides, dark sunscreen, false colors, etc. If you want UVB/UVC, you would need a specialized lens anyway (apart from some lenses with marginal UVB transmission). For that the cheapest option is probably to build one or buy one for industrial/technical use (like this one). The only example I know of a modern (discontinued) lens that works well in UV and IR is the Canon 40 mm f/2.8 EF STM, which I own and have used with nice results. Good candidates are pancake lenses, and probably 50 mm f/1.8 lenses with simple double Gauss designs. Jonathan measured two of them to my knowledge (link 1, link 2), and they pass some UV. Here David collected some information on autofocus UV-capable lenses. Given the great amount of available data for IR, to find a lens that works well in both UV and IR it is only necessary to test it for UV and see how it behaves in IR on some database. Examples of IR databases: link 1, link 2. I would encourage people to test modern lenses, and maybe we should put a section in the lens sticky about modern accidentally UV-capable lenses.

This new lens has a simple optical design with 6 elements in 5 groups (a double Gauss) and it uses no special glass. The lens covers an APS-C image circle, and it has autofocus. It's currently only available for Sony E-mount cameras. If it has a nice UV transmission and doesn't have problems with hotspots, it could be a nice everyday lens for general UV/VIS/IR photography. https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://m.dpreview.com/news/9123607864/7artisans-aps-c-27mm-f2-8-for-sony-e-mount&ved=2ahUKEwiBirLps-iFAxVa9AIHHUl8AjYQFnoECBQQAQ&usg=AOvVaw2LHk05WpBrbcHd1cR5Yexp https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://7artisans.store/products/27mm-f2-8-af-aps-c-lens-for-e&ved=2ahUKEwiSzf3WtuiFAxVi_rsIHXAfBQUQFnoECBwQAQ&usg=AOvVaw074MOuEPEcXL_h5raltmiz

I saw that there was a Leitz Focotar-II 100mm f/4.5 for sale at eBay. https://www.ebay.com/itm/285810363319 The price is reasonable for such a good and also rare lens. I think I paid a bit more for my copies. An enlarger lens much better suited for UV is the Focotar-2 50mm f/4.5 Several other versions of 50mm Focotars are almost as good, but a few types are not that suitable for UV. If anyone is tempted to get a 50mm Focotar, please check my evaluations here: https://www.ultravioletphotography.com/content/index.php?/forum/639-uv-lenses-non-helicoidal/ The 100mm Focotar-II is a rather rare lens, produced in small batches, totally maybe 2000pcs, if I remember correctly. Adapted with a suitable helicoid it is a very sharp lens for general photography and especially for close-ups. It is usable for UV to some extent as the shortest wavelength cutoff is rather deep. However the slope of decaying transmission is unusually gradual starting rather early, close to VIS. There has been a rumor that this lens was excellent for UV, so I have bought and tried two copies of them, with different production dates, as I suspected differences over production-time. I returned the first one, that I found lacking for UV, but kept the second as it is such a nice lens for VIS. The second one I got, had a serial number very close to the one copy owned by one of our members, that believed it had a good deep UV-transmission as he got reasonably good images when using the lens.

A friend has suggested that the Voïgtlander Nokton 25mm f0.95 in m4/3 mount is a good UV lens ?

There's not much information I could find on these lenses. As always, I have no affiliation with the seller. https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://wavelength-oe.com/application-notes/uv-lens-detectors/&ved=2ahUKEwjaloHY8JmDAxW1cPEDHXX4DfUQFnoECBkQAQ&usg=AOvVaw1B0AN844MuygAHm6tXEKee https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://wavelength-oe.com/wp-content/uploads/2020/02/UV-Lens-Detectors-Application-Note.pdf&ved=2ahUKEwjaloHY8JmDAxW1cPEDHXX4DfUQFnoECBoQAQ&usg=AOvVaw3fy3QIx9Ur54cGyzp4axIz

UV highlights often record non-linearly. I can take a shot and, upon review, the histogram might show exposure peaking near the middle. Add perhaps 1/3 to 2/3 steps more exposure and the histogram is close to or crashing into the right side. This is all done with EL-Nikkor closed down to the same aperture and camera on manual. Light appears the same. Is there something about UV light that causes this? Thanks, Doug A

Finished with all the posts, feel free to read and reply Triggered by Kai's thread (https://www.ultravioletphotography.com/content/index.php?/topic/5345-uv-photography-with-a-tilt-lens/), I decided to run some tests of the T/S-lenses. For this, I used the ones I have (17, 24), plus some which I managed to borrow from a friend. I might try to find one of the longer T/S-lenses on ebay, as they are fun to work with. Fortunately, today's weather was overcast, so I managed to get the shots with about the same lighting conditions (at the end I had to hurry else it would have been lightning conditions ). Cameras: UV: Canon EOS 6D, UV b/w by Maxmax IR: Canon EOS 6D, 700nm conversion by Sven Lamprecht VIS: Mobile phone Lenses: TS-E 17mm f/4 L TS-E 24mm f/3.5 L II TS-E 45mm f/2.8 TS-E 90mm f/2.8 TS-E 135mm f/4 L Macro Extenders: Canon Extender 1.4 II Canon Extender 2.0 II I had the cameras mounted on a tripod, but with every change of lenses or filters the position will have changed just a little bit; also I did not take the photos in the order in which I present them, so don't be suprised if there is large change in the field of view. Finally, focussing was a bit tricky (will have to get some reading glasses or one of those magnifying gadgets for the camera), please don't be too harsh. This is especially true for the UV-photos with the 90mm-lens. Five of the UV-shots are takens with an additional S8612 filter, just to get rid of any IR-leaks. I've observered many times, that the S8612 is not really neccesary, escpecially with my Soligor 21mm, but decided to make sure; and indeed, there are couple of shots where there is a difference. Due to the upcoming thunderstorm, I only had time to do a full test in normal-position, plus a couple of tilted or shifted shots with two lenses in UV. I might try another test with my FS-camera in the next couple of weeks, just to see how deep the lenses go into UV, perhaps also some more fun with tilt/shift; but don't hold your breath, work is interfering a lot at the moment. Processing: UV: I only converted to b/w (ooc there is some blueish tinge to the photos) and did global adjustment of exposure, to get the histogramms close to each other. The exposure is noted in the description of the photos. IR: CLiR profile number 5, no further adjustments (there are some differences in the colour casts of the lenses) VIS: nothing If you're interested what's in the photos, it's nothing exciting, just a view in my home-town of Leonding in Austria. Chose this spot because it's not too far away from my place, and it has grass, a field, trees, some buildings, and sky in it. Export was done from lightroom, 1500px long edge, quality 100%. Now, without further ado, the first photo, VIS:

This lens has an old Cooke triplet design, with just 3 elements in 3 groups. It produces bubbly bokeh. https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.ttartisan.com/%3FLens/185.html&ved=2ahUKEwjDi8f54NWAAxVdcvEDHYpcAzEQFnoECA4QAQ&usg=AOvVaw2q5PGRTeKkQ3_qzGmvYf4G https://www.techweekmag.com/news/photo/new-ttartisan-100mm-f28-lens-with-bubble-bokeh-effect-unveiled/ A simple design sometimes means deeper UV-reach. Maybe this lens is a good candidate.

This is a stretch of the forum's general theme as its link to UV is only the recent topic about hummingbirds. This is only partly about visual iridescence. I hope I am forgiven. Last week I was out searching for suitable sites for photos when I stumbled over something I think are very interesting. I had heard about a small nature preserve with bank swallows. When I got there, without any camera, I found a group of nice ornithologists too looking for a more rare visitor, the Bee-eater. They had cameras with fast loong fast tele lenses. The sand bank is fenced off to protect the bank-swallow colony. You have to stay maybe 40m back from the brink. That beautiful bird is rarely seen at my latitudes. It has happened a handfull of times this millennia. It was a privilege just to see the bird hovering in the sky. There is/was a pair feeding small ones inside a deep nest hole in the sand bank. I decided to try to get some images myself. The following day and the day after I got there better equipped and had some luck. The first day the birds only took dragon flies, the second I saw bumble bees, butterflies, and bees in their beaks too. Here are a few of my better images. The last five are from a bird-landing sequence taken at 10 Frames/s Telyt 560/6.8 + novoflex 1.5x extender all images except for the sky image, then Canon EF 400/4.0 IS + EF 1.4x extender

The glass types used in camera lenses are the main limitation for UV reach. Flint glasses are generally the worst for UV transmission, and very dense flint glasses start absorbing already in the blue-violet portion of the spectrum, and look visibly yellow. If the glasses used in a lens are known, as well as their thicknesses, one can roughly calculate how deeply that lens will transmit UV, and most importantly one can know in advance which lenses wouldn't work. This ignores coatings and optical cement, of course. On this website (written in Italian) one can see various drawings of lenses with the glass types shown: https://www.nocsensei.com/

If f/2.8 is not fast enough for you, here's an f/2 lens. The focal length is about 47 mm. The lens is not yet optimized for "buildability". Also, the distance from the rear element to the sensor required for infinity focus is less than that of lens #2. Mounting a helicoid would be more difficult. The lens does not correct for chromatic aberration. Lens simulated using WinLens3D Basic. Simulated at 340 nm. The lens has some barrel distorsion and vignetting at wide apertures. I will post more detailed information when I will optimize the lens for buildability.

I have lately bought a few more Canon TS-E lenses to complement the TS-E 24mm I got a long time ago. My goal was mainly to use them for NIR Photography. After my last published topic Kai asked for information about the UV-reach. https://www.ultravioletphotography.com/content/index.php?/topic/5846-a-visit-to-borgeby-slott/#comment-62641 Here is the result of a sloppy quick test without a high power light source and integrating sphere. I just used a collimated beam from my deuterium light source and then scaled the graphs "to taste" to a level I guess is reasonably correct. The measurements as usual made with my Ocean Optics Flame wide-band UV-VIS-NIR spectrometer. Due to the truncated light-source there is only valid information up to the violet band. Here I only present a narrow wavelength-band with the valid information in the mid part. Tested lenses and their graphs are Canon TS-E 24/3.5 L. Purple Canon TS-E 45/2.8. Red Canon TS-E 90/2.8 Black It seams like all three lenses are marginally usable for UV, but that the TS-E 90mm is best.

This lens is similar to the previous one, but has a longer focal length and is better corrected. Like the previous lens, it is not corrected for chromatic aberration. The focal length is about 55 mm, and the maximum aperture is f/2.8. Optical scheme: Lens at f/2.8, ray angle of 14° (covers APS-C): The lens actually covers larger sensors, at the expense of vignetting and barrel distorsion. Here's a 30° ray angle: At close focus distances (here 150 mm), some field curvature emerges: Lens at various apertures, 14° ray angle, infinity focus: There's plenty of space for the aperture, and also there's room for an helicoid at the rear. The most challenging part is the 0.5 mm gap between element 2 and 3.

Do we need a dedicated lens design section? Here's a lens I designed using WinLens3D Basic. The optical layout was inspired by Llewellyn Optics's 6 mm M12 lens available on MaxMax site. Link: https://maxmax.com/uv-lenses/lenses Here's the design posted on the site: My lens uses Thorlabs elements, all made of fused silica (the lens is not corrected for chromatic aberration), and (barely) covers an APS-C sensor (judging from the ray tracing graphs below I'm guessing the corners would look dark). The software gives an image distance of 31.7 mm (I'm guessing this is the distance between the rear element and the sensor). Here's the optical layout: Below the ray tracing drawings. Maximum ray angle of 35°, object points set at linear height, but are not projected linearly by the lens, they are "squished" at the edges, thus there's probably barrel distorsion. f/1.4: f/2: f/2.8: f/4: f/5.6: f/8: I would say the lens is kind of usable from f/2.8, and should be quite sharp from f/5.6. Probably the biggest challenge in building it is fitting an iris in that tight space. As for the focal length, I don't know where to read it. I could work it out from the aperture, but at this point I'm not sure about what the software is doing. Here's some information: I posted large images, hope it isn't too confusing. I can re-upload them if necessary.

The Raspberry Pi HQ camera has shown good results for UV photography. Below a couple of topics in which this camera has been discussed: https://www.ultravioletphotography.com/content/index.php?/topic/3883-raspberry-pi-hq-camera-12mp https://www.ultravioletphotography.com/content/index.php?/topic/4178-uv-safety-warning-reaspberry-pi-hq-affordable-fast-uv-sensitive-sensor Universe Kogaku makes two 6 mm UV lenses, one with a fixed aperture of f/2.8 and the other one with a variable aperture from f/3.5 to f/16. Both lenses cover a Raspberry Pi HQ camera sensor (diagonal of 7.9 mm). The f/2.8 lens covers a 4.8*6.4 mm sensor (diagonal of 8 mm) and the variabile aperture lens covers a 5.2*6.9 mm sensor (diagonal of 8.64 mm). This is the datasheet of the variabile aperture lens: https://www.universeoptics.com/wp-content/uploads/UV0635BCM-1.pdf Also, this lens has a C-mount. These lenses, as the other UV lenses from Universe Kogaku, are not corrected for chromatic aberration. One could rear-mount two 310 nm bandpass filters, to reduce angle-of-incidence effects, if this doesn't degrade image quality too much. One such filter could be this: https://www.edmundoptics.eu/p/10nm-cwl-125mm-dia-hard-coated-od-4-10nm-bandpass-filter/33098/ Of course I'm thinking about a monochrome-converted sensor.

This YouTube channel (https://www.youtube.com/@invisiblerays) has some videos on UV/IR photography. The latest videos uploaded show footage taken with Universe Kogaku lenses. These lenses have been already discussed on UVP, for example here: https://www.ultravioletphotography.com/content/index.php?/topic/4784-uv8040bk2-does-it-make-sense These lenses are not chromatically corrected, as they only use one type of glass (fused silica), thus they need to be refocused when changing wavelength. From the videos below, image quality looks to be pretty good, and there's not much chromatic aberration visible (I can't see any of it). They offer lenses from 6 mm to 105 mm, but only lenses from 35 mm cover an APS-C sensor (actually not, as the diameter of the image circle is 22 mm, which is the side, and not the diagonal, of a Canon APS-C sensor, but maybe they cover a few extra millimeters). Two videos: https://youtu.be/6Rok76Quulk https://youtu.be/NvtFJsU8bTM

Browsing YouTube I found this video: https://youtu.be/TlsS3rUjg8c [the site is acting weird, at least on my PC, so I cannot embed the link] The uploader warns not to watch the video as it is boring, and I haven't watched the lens-building part. What I find particularly interesting is the beginning of the video. It shows a modern f/0.95 lens next to an older f/4 enlarger lens in UV. The enlarger lens doesn't show any false color, and the modern lens has a lavender tint, as expected. But actually it doesn't look too bad, and it seems to transmit a surprising amount of light. Maybe some f/0.95 lenses could be interesing for UV photography if deep reach is not a priority.

I have found a software-tool for setting up and planning for photo stacking (not macro) and using Tilt-shift lenses. The Lumariver Depth of Field Calculator : https://www.lumariver.com/lrdof-manual/ It is also usable to set up an optimal hyperfocal-distance setting or optimal DOF for one shot. The tool is very powerful and maybe a bit difficult to grasp at first, but after a while it becomes increasingly more helpful and easy to use. I am still learning more each time I open the app. There are several tutorials on the site.

While discussing a problem with filter retaining ring replacement, I saw again this Amazon link from our member Enrico. It brings up some rubber filter wrenches which can be very useful if you have ever needed to dismantle a lens or any of its parts. Then if you scroll down the page, you see other tools like the wrap-around filter wrenches, the metal spanner wrenches and a nifty set of camera screwdrivers. I'm not sure how long this link will last, but here it is. Lens Tools Link [Our usual disclaimer: UVP, Andrea, and Birna are not affiliated monetarily with any commercial website and gain no benefit from any member's purchases.]

The OMDS M.Zuiko 90mm f3.5 macro pro lens is launched today - much YouTube marketing stuff but no transmission profiles that I could find. For Oly shooters, this lens seems to be best for visible macro field work, or just normal mid telephoto as this is micro-four-thirds and 35mm equiv is 180mm - claims you can do handheld focus stacking in camera, but we shall see. Probably really good for UVIVF at night outside. It accepts Oly 1.5 and 2.0 teleconverters and STF-8 ring flash. Claims about 10 cm (4 in) minimum focus distance. I will bet that it doesn't pass UV, but will see when it comes next month. I did order it as I do a lot of flower closups in the visible for teaching. Nice thing is that the filter size is 62mm, which is the hot mirror size I already have for my normal vis photo zoom lens. More when it comes.

Hello spectral venturers, has anyone experimented with FE lenses for UV/IR? I've been searching for FE lenses for Sony mirorless full-frames cameras, suitable for UV/IR, out of curiosity and for convenience as opposed to adapting lenses. I tried the Samyang 45mm 1.8 FE. I know, the aperture seems too large for UV capable lenses but the number of elements (7) in the lens is the same as its f/2.8 siblings, so I gave it a try. The lens had hotspots in IR and a heavy color cast in UV (loss of contrast). Manufacturer says that the Samyang 45mm 1.8 has "7 elements in 6 groups, including two aspherical elements and one extra-low dispersion element. There's an Ultra Multi-layer Coating to help reduce flare and ghosting." Not being adept around lens construction, I now realize there is more to a UV capable lens than the number of lens elements. The limited knowledge I have tells me that similar Samyang FE lenses (in the so called "tiny series") would be made of similar types of glass and therefore be unusable for UV (IR). So I have to look elsewhere. I could pull up technical data about lenses from other manufacturers. There is hope, though, for mirorless lenses and UV - I can see that the Sigma's 30mm f/1.4 DC DN (APS-C lens) works well. Thanks

I have Sigma's 30mm f/1.4 DC DN lens and it passes UV well enough for flower portraits. But in search of more working room I saw a Sigma 56mm f/1.4 DC DN on B&H. B&H specs says that the 30mm has two aspherical elements and one special low dispersion (SLD) element, and the 56mm has two aspherical elements and one high-refractive index element. The similar number of elements in the 56mm seems like it might pass UV, but I don't know if the asphericals are the same, or if the HRI element in the 56mm would prevent it passing UV. Has anyone tried to use the 56mm?

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. It is hard to find lenses made specifically for UV-C. But for some years, 254nm was the main wavelength used for printing transistor and microprocessor circuits on silicon wafers. These were made to have perfectly flat fields, large apertures in order to avoid diffraction, and extremely high resolution. To achieve the highest possible resolution, these lenses are optimized for a single wavelength. These lenses could cost hundreds of thousands of dollars (their more modern replacements cost millions). They were among the most perfect lenses of their time, and they could use very exotic materials. Sometimes these come up for sale on eBay or industrial salvage sites. That's how I got this Tamarack Scientific 254nm 1/5x reduction lens. The lens alone weights 10kg!

Beach huts are common by some beaches. In the area by Skanör at the southwestern tip of Skåne they are standardised in shape, 2m x 2m with a small 2 x 1m veranda. Here is one of the images I got when testing my Irix Firefly 15/2.4 lens, with a small putty-mounted 850nm filter disc at the rear. Shrunk to 50% of the original image. Those huts are placed in a safe distance from the sea to avoid being lost during winter storms. That has lately been a rather common problem in this region. Several other huts were saved the very last moments from floating away during a winter storm last winter. I like the dramatic sky and cloud images you can get with wide angle lenses.

I did some web search for lenses suitable for IR and found something that might be interesting. My primary source for information is Edward Noble's site: https://www.edwardnoble.com/hotspots All Olympus lenses here get high ratings. They look very promising to use for IR, if they also are sharp. Unfortunately Edd's site is not quite clear about details about other resulting lens aberrations, except in text comments about the very good lenses in his list. There is a Swedish site with a blog written by the founder of a major photo equipment web shop. The Captain's log, where he tests some old lenses very much in detail comments them and show high resolution test images. (if you click on the test pictures for each lens, they open up to the 100% image of the image.) Interestingly he is doing the testing mostly on Fujifilm high resolution big sensor cameras, so the test information is beyond the normal full frame area. https://www-cyberphoto-se.translate.goog/captains-log?_x_tr_sl=ja&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=wapp The article list is long and in chronological order, not easy to find a specific lens but if you do a text search for Olympus many of the Olympus lenses in Edd's list can be found. They seam quite good and sharp on big camera sensors too.