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If you were considering a Zeiss IR lens the opportunity has gone. I have just been informed by Zeiss that their ZF-IR infrared lens line has now been discontinued and it sounds as if old stock has been bought out by industrial dealers.

Note: Please bear with me on this topic. I'm not going to be able to get everything posted all in one sitting because we have lots of things going on here at UVP Headquarters - West. MaxMax makes 3 Infrared bandpass filters: https://maxmax.com/filters/bandpass-ir These are beautifully made filters. Each has a shiny coloured side (dichroic?) which gives them their designation as blue, green and red. The color designation has nothing to do with how the raw or false colours appear in a finished IR photo - at least as far as I can determine currently. On the linked page Dan has shown some RGB stacks made with the 3 filters. My initial experiments were not quite that colourful, but that's OK. I'll get there eventually. For my first experiments I had simply wanted to explore the basics. I always like to look at the demosaiced raw photo before any RGB multipliers are applied to set the white balance. This raw composite gives an idea of how the camera is really recording through its Bayer filter. The excellent app Raw Digger outputs a very basic raw composite with only minimal contrast/saturation curves. Gear: Nikon D600 + some 35mm lens + Sunlight Measurements of the raw colour casts were made over the white Spectralon. Then a square of the fully saturated colour was added to the raw composite. IR BP Blue max transmission about 93% half-max width about 90 nm f/3.5 for 1/500" @ ISO-400 Like other IR-pass filters which pass some high red, we get lots of false colour with the BP Blue. It has a strong Orange raw colour cast. IR BP Green max transmission about 90% half-max width about 65 nm The colour cast for the BP Green is very unsaturated. When the saturation is pushed, we can see that the colour cast is Red with about a 25% contribution from Blue (so headed towards Cerise, I suppose). f/3.5 for 1/500" @ ISO-400 IR BP Red max transmission about 85% half-max width about 37 nm You can see why the BP Red requires a longer exposure time. It's lots less wide and peaks out there in the 900s. The colour cast for the BP Red is definitely Magenta after full saturation is reached. f/3.5 for 1/40" @ ISO-400

This topic is a spin-off from this topic, using different filters to those in that topic's title: https://www.ultravio...__fromsearch__1 This is about getting full (and, of course, false) colours in IR. It uses the same techniques described for UV in this topic: https://www.ultravio...__fromsearch__1 In outline, this approach takes 3 images in different parts of the NIR spectrum, and uses these for the RGB channels to get a full colour image. To get the three images, the following filter set was used: 700-800nm range: Midwest Optical BP735 + R72. (The R72 is used to block the red leakage from the BP735.) This forms the blue channel. 800-900nm range: Midwest Optical BN850 900nm+ range: Midwest Optical LP1000 These filters give the following transmssion curves. The curves have been adapted to include typical CMS sensor sensitivity variation across the spectrum, and have been adjusted such that their heights are the same (as differential exposures are used to overcome the different transmission levels of the three filters): The first results are below: The first image is a standard visible light shot. The second is the full-colour IR shot. It is disappointing in that it shows only faint colouring. But ... The third image is the full-colour IR shot with the saturation wound right up. Colour at last! White balancing was done against the white PTFE tile. You can see that the 18% grey target at the back is not so grey in the IR! Most of the foliage (inc. the red poinsettia leaves) is neutral - I was expecting a slight cyan tinge as UV reflectance by foliage decreases slightly across this part of the spectrum. The effects of manmade colourants are always interesting. Note how the green marker pen and green booklet have quite different colours to each other in IR. But the blue marker pen and blue book both become yellow (i.e. absorbing in 700-800, reflecting/transmitting in the 900+ band). And the red printing ink is completely transparent across the frequency range. The red berry-like things and the darker red parts of the roses in the vase have come out cyan, indicating that whatever colouring chemistry is reflecting red in the visible region is continuing to reflect light as we move into the 700-800 and 800-900 bands, but not in the 900+ band.

Peterborough UK River Nene Embankment 'Willow Tree' IR images taken on a frosty / sunny day, 17 January 2023 with a 'full spectrum converted' Leica T (Type 701) / Leica TL 11-23mm / URTH 720nm IR filter . Full spectrum conversion by Alan Burch, "Infra Red and Full Spectrum Camera Conversions" IOW UK. The Leica T is a 'great unloved' Leica APS-C ICL camera partly because its AF can be too slow – but in manual focus mode, with magnified 'live view' it's fine. The T does not have an integral live view EVF; it relies on a hot-shoe fitting accessory EVF – made by Epson but 'badge engineered' Leica'. The long discontinued 16.2MP Leica T (only available s/h) is the cheapest ICL Leica APS-C camera. My first pix posted to the forum. BW, dunk

In March & April of 1973 there was a "UFO flap" in Piedmont, Missouri, east of the Ozarks. I decided to take my cameras with IR film down there to see what I could capture. I had with me a Yashica rangefinder loaded with Ektachrome Infrared, an Agfa rangefinder with Kodak High Speed Infrared and another rangefinder with 2475 Recording Film (ASA 1600). I saw some strange lights but never caught them on film. I did however snap some sidelights from the journey. Here's a few of the IR photos. Caught some ducks by the roadway and captured them from out the car window on Ektachome Infrared. t Next, a Kodak High-Speed Infrared timelapse, about 10 minutes. This pic shows a rising star and a couple of planes with blinking lights flying by. Nothing unidentified here. Another pic on High Speed Infrared. A rainy day showing the motel where the famous UFO icon J. Allen Hynek was staying. This was the only motel in town and it was full so I got some valuable experience sleeping in the car and listening to Pink Floyd's recent Dark Side Of The Moon album on 8-track. My desktop back home on Ektachrome Infrared. The 'UFO detector' I took with me-- the top half of a modified metal detector that I added a Geiger counter and RF field strength meter to. (Those old White's Electronics metal detectors had a lot of empty space inside). Other artifacts in this pic-- an old Press 25 flashbulb with opaque IR coating, a red apple, a black golfing glove and a 400V Heathkit power supply.

After messing around with a Sony Nex-3N for 2 years I finally got to modify my Sony A7 to full spectrum. It was pretty easy but it was still my back up camera for wedding shoots I used to do with my ex partner so I couldn't risk ruining it. Now that I'm alone again I didn't need it for that anymore so I finally got the chance to take it apart. I'm very happy now that I finally have a full frame camera dedicated for IR. First day results look promising. #1 is Sony A7 with Samyang AF 45mm f/1.8 FE and Lee 115 + GRB3 stack #2 is Sony A7 with Tamron 17-28mm f/2.8 Di III RXD and a Zomei 850nm filter

A friend sent me this YouTube link for obtaining IR images with Sony cameras by the use of a magnet! I don't own a Sony camera so can't test. I do wonder what the magnet does for the other components of the camera! https://www.youtube.com/watch?v=2mug6xGPdhY

I've been using my new Aerochrome filter set a lot these past weeks. It produces really articulate colors. At a point that I don't think the original film necessarily did better. (plus digital offers a completely different dynamic range, making digital IRG photos very disctinct from the OG) Until now I haven't noticed any plant health information that isn't distinguishable with the naked eye : young leaves and show pink, older leaves red and the more they wither the more the lean toward orange brown and yellow until it is completely dry and shows grey. My guess is that aerochrome is not intended to be properly white balanced like I do with my photos, and that therefore it shows a strong dichotomy beetween cyan dead plants and pink healthy plants. It is maybe easier to tell the different beetween cyan and pink that beetween grey and green. So yes from what I've seen nothing special is reavealed, it's just way more beautiful than the usual boring green. So to recap my setup for these pictures is : filters : Midopt TB550/650/850 + Lee "Flesh Pink" + GRB3 (+Cokin diffusion filter on some shots) Camera : full spectrum Canon 1200D The channels are swapped in darktable, no IR substraction is needed. I work from sRGB jpegs. No color edits at all. I edit the contasts in Lightroom.

Grabbed some pistachios after work and decided to try UVIIF. I was kind of tired and things didn't go as well as expected. First mistake was using stock Pentax 645z. Hey, it works great for UVIVF, so why not here? Because it takes a very long exposure to force enough IR thru the stock sensor filter. Will use full spectrum camera next time. There are other questions. 1. Using Nemo torch or Adaptalux UV arms Is it enough to use a 25 red or Hoya 72 filter on the camera lens? Or is the Tiffen Haze 2E also needed to block UV? 2. Does my custom IR landscape white balance work here? This isn't vital since I shoot Raw, but nice to get in the ballpark. Thanks, Doug A

In the 1990s I decided to revisit IR photography using my medium format Pentax 6x7 SLR. It was a clunker of a camera weighing several pounds with an additional lens. I took it on only two or three major trips due to its size and weight. I found a new film in 120 size called Konica Infrared 750nm. It was also available in 35mm. From what I can find now it was discontinued in 2005. Here's a couple pics from a stopover in Fiji on the way to New Zealand in 1995. I was using an SLR so I decided to use a #29 dark red filter so I could frame and focus through the lens normally for bright daylight shots. Next stopover was in the Cook Islands. The red filter didn't yield the black sky I prefer with B&W IR but using opaque filters with an SLR sorta needs a tripod which I didn't have. I never did try the 35mm version of the film but I did like the better tonal range than was possible with Kodak High Speed Infrared film. (Had to change the dimensions of the fourth by one pixel to get it to upload.)???

While shooting a cucumber in UVIVF, I forgot to add the Kolari hot mirror filter. The Tiffen Haze 2E took care of the UV. Cucumbers fluoresce in both visible and IR. So what would the proper designation be? Thanks, Doug A

I spent some time yesterday taking many images of this unremarkable piece of plastic fantastic. I got these on a flea market the other day, thinking they were cool, but given that they're made from pretty cheap plastic, I might have changed my mind on that over time. Regardless, it was interesting "investigate" them. First thing I did was an IR tri color, using the GRB3 method I discovered recently. Very underwhelming, but expected. Next thing I did was I illuminated the glasses with three different IR filtered LED lightsources, a green one, a blue one and a 395nm one, I recorded the fluorescence in IR for each using my 850nm longpass filter and made a tri color image out of them afterwards. Lastly, I opened up the lens all the way to f/1.4, since I knew I would need a lot of light. I mounted the blue spotlight I was using beforehand and I did an IR tri color of the IR fluorescence under blue. I'm not exactly sure if I learned anything from this, besides maybe the fact that the orange shot glass really likes to fluoresce, but it was interesting, still. I would like to investigate more objects this way later.

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:

The following experiments are inspired by the findings of @Christoph Here is a series of pictures with my full spectrum canon 1200D and a stack of these three filters : Midopt Triple bandpass 550/660/850nm Lee "Flesh pink" gel GRB3 from Tangsinuo The transmission curve of the three filters combined should look something like this : Both the green and the IR spike are heavily filtered. When the TB is used alone, it seems to suffer from a very weak red transmission : without the GRB3 the red channel records as much (if not more) IR than red, requiring IR subtraction of 100%. The green spike transmission to the contrary is very powerful. To the eye (at least mine) the filter is green. I'm not sure how bright humans are able to percieve red at 660nm, its pretty deep already. I then decided to reduce the transmission of IR and green equally to give room for the red transmission. The GRB3 is used to minimise IR contamination in the RED channel and the Lee gel is used minimise green contamination in the blue/IR channel and to make it more or less match the level of output of the red channel. The blue channel stays very underexposed compared to the two others, and is brought back in white balance (pretty extreme : lower than 1900Kelvin). The exposure value with these filters ranges from 1/50s to 1/100s in sunlight at f5.6, 200iso. It's a very dark combo. All the pictures are channel swapped in Resolve from the camera Jpegs, the process is video ready. No saturation was added and zero IR substraction is needed. The fact that IR transmission is cut by 90% by the GRB3 causes some green leaks to be percieved in the Blue/IR channel. This leads to the need to apply a hue correction to the sky in order to make it look properly blue and not purple-ish. This process is simple and non-destructive. The original color of the sky after channel swap : Important notice : The channel swap causes a significant decrease in contrast and micro-contrast. For a moment I thought this was due to the Jpeg compression but it is not. Do you remember this law ? Y = 0.1 Blue + 0.6 Green + 0.3 Red It is actually crucial in understanding why the images look better unswapped. It describes how the human eye is sensitive to luminosity. The green value is far more decisive in the percieved brightness of an object than the red and blue values. A quick exemple Unswapped image : Swapped image : it looks less detailed and dynamic. The contrast beetween the bright grass and the dark trees is lessened Swapped image but with the "preserve luminance" box ticked : the image is sharper and more alive. (Click on the image and use the viewer to compare both instantaneously.) Explanation : The grass in the unswapped image appears turquoise. Let's make it cyan for the sake of clarity. The trees appear blue. Cyan RGB values are (0; 255; 255) Blue RGB values are (0; 0; 255) The minimum luminance(Y) is 0 and the maximum luminance is 1. Y(cyan grass) = 0.1x Blue(255/255) + 0.6x Green(255/255) + 0.3x Red(0/255) = 0.7 Y(blue trees) = 0.1 x B(255/255) + 0.6 x G(0/255) + 0.3 x R(0/255) = 0.1 in the unswapped image the contrast beetween the brightness of the trees and the grass is important : Y=0.1 versus Y=0.7. Now, let's do the same for the swapped image where the grass is magenta and the trees are red. Y(magenta grass) = 0.1 x B(255/255) + 0.6 x G(0/255) + 0.3 x R(255/255) = 0.4 Y(red trees) = 0.1 x B(0/255) + 0.6 x G(0/255) 0.3 x R (255/255) = 0.3 in the swapped image the contrast beetween the brightness of the trees and grass is less important than in the original image (Y=0.3 versus Y=0.4) In this chart the colors are ranked by luminance. white Y=1, yellow Y=0.9, cyan Y=0.7, green Y=0.6, magenta Y=0.4, red Y=0.3, blue Y=0.1, black Y=0 As you can see here the brightness of Magenta and Red is very close as opposed to cyan and blue that are very far apart. So that's why channel swapping sometimes makes the image lose quality. A solution to this is to tick the box "preserve luminance" in the channel mixer. It doesn't work in every situation since it makes the yellow objects turn way darker, leading to an unnatural look. Ticking the box also makes the sky way brighter. It's a tradeoff that has to be made for each individual picture. In the selection I posted above, a few have the box ticked and most don't.

I have been taking a lot of photos lately. This time I decided to investigate a pair of cucumbers. I illuminated them with a halogen spotlight, which emits enough light for IR, visible and UV. IR tri color is using my GRB3 method UV is taken with a ZWB2+QB39 stack (which surprisingly does not leak significantly, even with halogen) I will also be including the individual pictures if anyone else wanted to take a shot at processing them (please, do post). I'd especially appreciate if someone managed to stack all 7 channels continually. I only could stack them by binning the visible and the IR part of the spectrum together. The pictures are in full hd so if you still have a 1080p display, you might want to enlarge. visible IR tri color 850nm+720nm+red Aerochrome simulation GBUV full spectrum individual color channels: 950nm longpass ~850nm band ~720nm band red band green band blue band UV band (400-350nm) I also decided to stack the images in Photoshop and pick the range stack mode, I got interesting results. All of the bands stacked: All of the bands except for UV stacked: IR only stacked: IR only stacked (normalized): Bonus: IR stacked, normalized and processed with Topaz Denoise AI: Here's the IR range mapped on the visible image: Here's the range between 720 and 850 bands mapped on the visible image:

Lately, I have been having much fun taking pictures of different objects in many bands and then combining the data I get in different ways. I have gotten many interesting results which I will share later but for now I would like to share images of this beautifully blue mineral I got on a flea market on saturday. The images are in full hd. As I usually do, I took several images of the rock in different bands. Three IR bands with my GRB3 method, a normal RGB image (as seen above), and a UV image with a ZWB2 and QB39. 950nm 850nm 720nm red green blue UV Out of curiosity, I also did a UV picture with the same exposure time, aperture and ISO with a 510nm longpass filter screwed on top of the two filters. I think the result was very impressive considering this was a halogen spotlight and not even the sun or some other better lightsource. This image was pushed by 8.612 stops in Darktable. Now for the more artistic interpretations. G-B-UV 950nm-850nm-720nm Aerochrome simulation 850+720+R full spectrum (850nm+950nm+720nm)-(R+G+B)-UV Edit: here's a full spectrum stack made with a hybrid method I developed using advice from both @Stefano and @Andrea B. (found in this thread): I think it looks much better. (stackmode maxium)-(stackmode median)-(stackmode minimum) stackmode range, normalized Brighter areas show where the minaral is the least consistent in its reflectance. It's very inconsistent overall.

Spent some hours in my usual spot, the local Botanical Gardens, in order to take a few pure IR-shots, for a change. Equipment: Canon EOS 6D, converted to 700nm, Canon EF 85mm f/1.2, with an extension tube, used mostly at f/1.2, because, after all, if one wants shallow DOF, what's better than a fast prime and an extension tube, right I've kept ISO to 100, and the time was anything between 1/160 s and 1/4000 s, because it was quite variable with sun, partly cloudy, fully cloudy; sunny and shady bits of the Gardens, etc. I have no clue whatsoever which plant I was taking photos of, and yes, this is nothing unusual for me, but this time around I really didn't care, because I was just looking for interesting details. Post was also minimal, using the CLiR-profiles with some adjustments, just the ones with the got a somewhat better treatment, and on those I used f/2.5 (spider) and f/4.5 (bee/fly/...).

Fisheye-lenses, to me, are kina like Lensbaby or the XR-Heligon, bad for everyday's photos but fun to take out for a spin a couple of times a year. Yesterday I took mine out for a walk by the river, and boy, is it tough to find something which really looks interesting with a fish-eye, although the IR-bit helps a little Canon EOS 6D, converted to 700nm, Canon EF 8-15mm, at 8mm, of course

As you know, all cameras react differently to IR light once they are converted to full spectrum. I don't know if this is really well understood so I wanted to start a topic and have your opinion about it. I just got the Sony f828 (the camera that can be converted to full spectrum with just a magnet) and I can now compare its fullspectrum colors to my Canon. Canon 1200D, white balanced full spectrum colors, no additional filters : Sony f828, white balanced full spectrum colors, no additional filter : The pictures were white balanced and saturated from the RAW files in Lightroom. The two cameras are pretty far apart as we can see from these pictures. They are also pretty far apart in terms of technology : the first is an 18Mpx CMOS and the second is a 20 years old 8Mpx CCD one of a kind RGBE sensor. Sony camera are known to not perform as good as Canon with the IRchrome filter. The images above indeed show that this Canon camera has a predisposition to record IR in the red channel compared to the Sony. Now do more recent Sony cameras produce blue SOOC like this one does ? I don't know... Maybe the sony users here can help me from their experience.

The fluorescence was very weak. I had to use ISO 800 with a 30s exposure to achieve this photo. I also had a relatively strong UV LED chip's entire output focused directly onto the banana (using the built in "zoom" feature of the torch).

As some of you might remember, I keep pet rats. Not for much longer since I am leaving my home to live in a dorm and starting my university studies. I took IR portraits of them some time ago, I will post some visible references as well. Despite what people usually think, pet rats are really smart, clean and affectionate. I routinely get licked and groomed by them since they consider me one of their own. So, very friendly animals overall. Kind of like dogs. They also clean themselves about as much as cats do. Portrayed here are Ceres and Xanthia of Lavan. They come from a certified breeder, so that's why the weird names. I also have a third girl named Apricot but I guess she was busy chewing on something somewhere when I was taking the pictures.

Continuing my studies in edible things, I decided to take pictures of some apples. visible reference infrared 850nm LED UV induced infrared fluorescence (850nm longpass, 365nm LED) UV (illuminated with 365nm LED)

A process for full-colour UV (actually, UVA) photographs using tri-colour separation images is covered in the thread at https://www.ultravio...__fromsearch__1 . An equivalent process for IR (actually, NIR) uses the same methods, but with different filters (and without the problems associated with the camera's low sensitivity in UV). In this post are some images which show typical results from these techniques. Unlike simulated Aerochrome images, no visible light is involved – the images are pure UV or pure IR. Just as a reminder, the tri-colour separation images used the following filters: UV: Red Channel: 380BP20 Green Channel: 345BP25 Blue Channel: 315BP25 (peak transmission at about 323nm) IR: Red Channel: CWL at about 1,000 nm Green Channel: CWL at about 850 nm Blue Channel: CWL at about 735 nm Camera in all images is a full-spectrum Sony A6000. Firstly a few shots showing groups of related items. Here are some printed materials (Visible, UV, then IR images; Lens = Focotar-2): Next, various containers with metal, plastic, and paint (Visible, UV, then IR images; Lens = Focotar-2). In UV, a lot of plastics come out as brown (i.e. increasing absorption as wavelength decreases) irrespective of their visible colour, and the same plastics tend to come out white in IR. (Oil-based paints similarly come out brown in UV.). There is also a glass of water here. In UV this is yellow, which is because of the absorption of shorter wavelengths by the glass; in IR it is blue, because of the increasing absorption at longer wavelengths by the water. The plastic bottle of isopropyl alcohol at bottom left shows a similar effect in IR. Now, some fruit and vegetables (Visible, UV, then IR images; Lens = Focotar-2). Relatively little colour, with the objects looking dark/rotting in UV and shades of white in IR. Glazed Pottery (Visible, UV, then IR images; Lens = Focotar-2): My long-suffering wife. The red hair in the IR shot is close to what it was like when she was younger. The skin has a slight cyan colouring, indicating higher reflectance at the shorter IR wavelengths (the yellow patches are probably down to facial movement between shots). The redness in IR of the visibly red bricks is noticeable. The UV shot shows up the freckles, and the sun-blocking effect of face cream (rather than specific sun-block cream) applied several hours earlier: the brown colour of the face cream area indicates decreasing absorption as wavelength decreases. The mauve of the T-shirt is interesting – indicates that reflection dips in the middle of the UVA range (Visible, UV, then IR images; Lens = Focotar-2): Non-glazed Pottery (Visible, UV, then IR images; Lens = Focotar-2): Finally in this sequence, a car windshield (Visible, UV, then IR images; Lens = Focotar-2). The UV image shows very strong absorption, especially at shorter wavelengths, which is not so surprising. But I was surprised to see that there was quite a lot of IR absorption, predominantly at longer wavelengths. The above UV image brings to mind what the great Richard Feynman said about the first atomic bomb test at Los Alamos: "They gave out dark glasses that you could watch it with. Dark glasses! Twenty miles away, you couldn't see a damn thing through dark glasses. So I figured the only thing that could really hurt your eyes - bright light can never hurt your eyes - is ultraviolet light. I got behind a truck windshield, because the ultraviolet can't go through glass, so that would be safe ... this tremendous flash out there is so bright that I duck ... So I look back up, and I see this white light changing into yellow and then into orange ... Everybody else had dark glasses, and the people at six miles couldn't see it because they were all told to lie on the floor. I'm probably the only guy who saw it with the human eye." Looking at buildings now, it is interesting that brick and roof tiles that are red in the visible also come out reddish in IR. So an IR colour image could almost be mistaken for a standard visible colour image - until you have a true visible colour image for comparison (Visible, UV, then IR images; Lens = Focotar-2): A couple of noteworthy points about the next trio of images: the window frames and doors in the buildings to the left are brown in UV because they are plastic coated or painted with oil-based paints. In the building just right of centre, the wooden beams, which are weathered to grey in the visible image, come out brown in IR: this is a typical rendition of wood in colour IR (Visible, UV, then IR images; Lens = Focotar-2): (Visible, UV, then IR images; Lens = Focotar-2): In this image, the columns are painted white using an oil-based paint, and so come out brown in the UV image (Visible, UV, then IR images; Lens = Focotar-2): The next image is a vertical panorama. This church is on a hilltop and is a reporting point called "Golden Ball" for aircraft flying in to the local airfield (Visible, IR; Lens = Focotar-2): The following image shows the limitations of this technique when using focal lengths shorter than 50mm (with an APS-C sensor) and dichroic filters. You can see the colour shift towards the edges in the IR shot, and the additional problems caused by the small diameter (25mm) of the UV filters (Visible, UV, then IR images; Lens = Soligor 35mm f/3.5 enlarging lens): Turning to landscapes, this is where IR is at its best. UV landscapes show very little colour, and of course haze in the distance is more pronounced (which might be an effect you want). Skies come out blue in IR (adding to the effect of sometimes appearing as almost normal colour images); this is less noticeable in UV, with skies often appearing white – perhaps as a result of the sky burning out, because if you deliberately under-expose you can get a blue sky) (Visible, UV, then IR images; Lens = El-Nikkor 105mm): I have added a funky fail in to the following trio: this was an IR shot where the fast-moving clouds caused their shadows to move while I was changing filters for the three tri-colour separation exposures (Visible, UV, IR, then IR Funky Fail images; Lens = El-Nikkor 105mm): I like this shot in IR – it almost looks like a normal colour image, but then you have the surprising white background. Also, another funky fail (Visible, UV, IR, then IR Funky Fail images; Lens = El-Nikkor 105mm): This IR image shows subtle variations in colour between different areas of vegetation. (Visible, IR; Lens = Focotar 2): In this trio, we see clearly the effects of atmospheric scattering: the distance in the UV shot is very hazy, and the IR shot shows blue-green colouration in the distance. The building with chimney stacks towards the top-left of the image is about 19 Km away (it is all that remains of a power station which used to be a major landmark for local light aircraft) (Visible, UV, then IR images; Lens = El-Nikkor 105mm): Note here the brown colour of the bridge in UV, which again is down to the use of oil-based paint. The IR image shows subtle variations of colour in foliage, and the white paint on the bridge is obviously not white in IR (Visible, UV, then IR images; Lens = Focotar-2): Finally, flowers. I have not included any IR shots here, because these always come out as white, although you can squeeze a bit of colour out of them by ramping up the saturation to extreme levels. But here we have only UV shots. As a general (but not universal) rule, blue and white flowers come out red – presumably because the colourant reflecting blue light doesn't stop reflecting at 400 nm, but continues into the longer UV wavelengths. (Blue flowers also come out blue in straight shots taken through a Baader U, presumably because the longer UV wavelengths just happen to be triggering the blue channel.) Wild Strawberry (Visible, UV; Lens = Focotar-2): Cornflower (Visible, UV; Lens = Focotar-2): Bindweed (Visible, UV; Lens = Focotar-2): Mock Orange (Visible, UV; Lens = Focotar-2): Campanula – note how the difference in visible colour does not come through in UV (Visible, UV; Lens = Focotar-2): Margerite (Visible, UV; Lens = Focotar-2): Sweet Pea (Visible, UV; Lens = Focotar-2): Dead Nettle (Visible, UV; Lens = Focotar-2): Dog Rose (Visible, UV; Lens = Focotar-2): And yellow flowers tend to come out slightly cyan, indicating more reflectance at shorter wavelengths. (These come out slightly yellow with the Baader U). St. John's Wort (Visible, UV; Lens = Focotar-2): Buttercup (Visible, UV; Lens = Focotar-2): Dandelion (Visible, UV; Lens = Focotar-2): Hawksbeard (Visible, UV; Lens = Focotar-2): The rest of these images do not follow those general rules: Geranium (Visible, UV; Lens = Focotar-2): Iris (Visible, UV; Lens = Focotar-2): Pansy (Visible, UV; Lens = Focotar-2): Mallow (Visible, UV; Lens = Focotar-2): Clematis (Visible, UV; Lens = Focotar-2): Loosestrife (Visible, UV; Lens = Focotar-2): Aquilegia (Visible, UV; Lens = Focotar-2): Snapdragon (Visible, UV; Lens = Focotar-2): Tulips. Flowers of the same species but with different visible colours usually look the same in UV, but these tulips show that that is not always the case (Visible, UV; Lens = Cassar S):

Yesterday I visited a local cemetary and took some photos in UV and IR (700nm). The UV-photos were taken with the EL-Nikkor 80 (no hotspot to be found here), and the IR ones with the 24 mm T/S-lens. Again chancing it without tripod I found that the focus shift of my Nikkor is quite noticeable, so I used LiveView with magnification to focus for the long-distance shots and then used my forehead in the traditional fashion to stabilize the camera for the photo, after turning off LiveView for composing. I didn't make a point of creating twins in terms of composition, so most of the subjects are not photographed from the same angle, etc. It's just too boring, and I think the differences show up all the same. The cube on the mound is a memorial to those who died in the last Great War, the obelisk is from the burial place of Sowjet soldiers, the archway is called "Heaven's Gate", and the others are just impressions. As a matter of fact, this time round I prefer the UV-shots, possibly because of the sombre mood, and the way the memorial and the gate stand out with their light colour.

This is a very informal topic, but I still find it interesting because it shows how deep learning models such as DALL-E 2 have "learned" what a NIR photo looks like (especially the Wood effect). I tried the same with UV, but only got UVIVF images, which shows how little known reflected UV photography is. These AI models are a reflection of what people know (and what is posted online). Not surprisingly, NIR photography is much more known than the UV counterpart. All images have been entirely generated using DALL-E 2. No edits were done, posted at full resolution (1024x1024). The prompt for all images is "Near infrared photography".