Interference filters are working with destructive interference. That is, they are made of many thin coats (sometimes as much as 30). The thickness of the coats are calculated such that reflection between each coat destructively interfere with each other at a given wavelenght hence the filtering effect. When you tilt the filter the distance the light travel is now longer and the effect disappears. These are typically great filters and can be very specific. Astronomy if full of them. Trivia: multiple of the wavelenghts will also be filtered. Usually that doesn't matter because it's not in the visible. en.wikipedia.org/wiki/Interference_filter
And this is exactly how the coatings work on our lenses - at least, most of them. It's easy to see how the filters are only applicable in certain wavelengths by shooting an infrared image with the sun in the frame - massive flare because the interference coatings were designed with the visible spectrum in mind (even though, as you mention, there are interference coatings for many wavelengths, often used when shooting astronomy-related subjects) These interference coatings are also how sensors block UV and IR light, typically, but they are more effective on the sensor because the light is coming from a more direct angle. Using such interference coatings on a UV filter at the 77mm size is less effective than using an absorption filter - but they too can have issues (some of them like the Zeiss T* UV will faintly fluoresce). That little segment of the video was mainly just to bring to light that there's a lot of different ways to do this, but more importantly that some manufacturers flat out lie about the capabilities of the filters and different filters - even good, expensive ones - will behave differently. :) Hope you enjoyed the video!
@@DonKomarechka The quality and wave length of the filters is determined by the number of layers and the type of coating. If you have interference filters in the visible (say like the H-alpha) and you tilt them you can immediately see with your eyes the same phenomenon of the filter color shifting. See www.baader-planetarium.com/en/baader-h-alpha-7nm-ccd-narrowband-filter.html It never occurred to me that it would be an issue in regular photography. But it is worst here because it occurs at wavelengths we cannot see. Good to know. Thanks
@@patricescattolin43 Baader makes some exceptional filters, I have their U-Venus filter and I wish they made it in bigger sizes... but it doesn't suit the intended application. The larger the filter, the more likely you'll have oblique angles to light, so this makes sense that the purpose and diameter have constraints. We're pushing the limits! :)
@@DonKomarechka BTW it's possible that this is the reason that most of the UV light filters didn't block the specific wavelength of the UV flashlights. The UV you have to deal with from the sun might be a different wavelength and that is what those filters are designed for. You'd have to test them in sunlight with a UV camera. I'm just speculating though.
This is fantastic. One of those examples that Don comes up with so often of how anyone can experiment and create unique images fairly easily and inexpensively. This one is bookmarked so I c can reference it later. Thanks!
Love Don, great episode guys. There are some awesome and unique shots there. A very creative way to use common objects to create stunning images. Thanks guys!
Oh, they do! I shot a selfie with them on, using a camera modified to capture UV light directly and the exact same safety glasses were completely dark: twohosers.com/the-two-hosers-photo-show-354-dkuv/
@@skakdosmer I had tried that for one of my initial experiments in studio Lau, interesting results! We didn't have ice cubes when we were recording this video though. I even thought it would be interesting to place the aquarium on a slab of dry ice, or somehow supercool the tank below the freezing point and then use even colder inks which would cause a nucleation event that would cascade the entire tank into freezing. Might not make for a great image, but it would be all sorts of fun!
Very cool, this has me excited to try this out! I've been wanting some good UV lights for a while so I appreciate the brand recommendation. Is there such a thing as *too* much UV flashlights?
Thanks for sharing, it's an interesting video. One small comment: it would be helpful, during the demonstration of the effectiveness (or lack thereof) of the UV filters, to move the filters in and out of the range of the UV light to show the colour of the light with and without the filter. Also helpful would be to do this interchangeably, in one take, with an effective UV filter and ineffective one for comparison. This is very minor, but IMO would make the point way more convincing.
Good point! However, this wasn't meant as a comprehensive review of every UV filter available, just showcasing a few with quirks to illustrate the point that many of them are made differently. We'd have to build transmission charts to really do it right, and I believe there is a LensRentals blog post that covered that in the past - and even that doesn't take into account for off-axis light and fluorescence of the filter. Still, you're right, swapping a good vs. bad filter in one take would be a good visual. :)
Very cool video, basically a professional version of stuff that I experimented with some months ago. I also noticed that cheap UV flash lights are bleeding a lot of visible light and that my UV filters are really not filtering UV at all. My plan was to use the same Noodler's uv ink that is used in the video, but I was to water my flowers with it to make them more fluerescent (just like you sometimes see people dye roses with colored water). I can report that this plan did not work at all and my flowers died within a few days :(
Apparently feeding invisible ink to flowers is unhealthy. In some of my early experiments I tried the same thing! I have wanted to revisit the concept with diluted ink and plant food in the mix to see if it helps, focusing on buds rather than already blossomed flowers to have a larger impact. There's always more to experiment with.
@@terriplays1726 then the next step would be make a solution with fluorescein. I have some fluorescein strips used by optometrists to detect problems with eyes or to fit contact lenses. It fluoresces a yellow-green colour and is biologically inert. Just too many things on my to-do list. :)
To the question why there is an angle dependent transmission and some filters perform better than others: All these filters are based on destructive interference, meaning that the thickness of the coating is specially designed so that the wavelength of choice cancels itself out. This is performed by overlaying a light wave that is purely transmitted with one that is first reflected at one coating surface, then back-reflected from the next coating surface to then finally exit the filter as the first wave did. If the distance difference between both is exactly half the wavelength, the addition of both waves will lead to zero amplitude. This is why coatings are very thin as the wavelength of visible light is around 100 times smaller than a human hair. When you tilt the filter the light is travelling a longer path and so the path difference between both beams doesn't match half the wavelength anymore. As one thin coating layer only targets a single path difference perfectly, any other wavelength will be transmitted as was shown for the cheap filter. This also holds true for filter tilting. More expensive filters, however, use the tricks of using multiple and thicker coatings. First, thicker coatings are designed to cancel out a wavelength that is much longer than the original one. However, if the original wave travels 3/2 or 5/2 or 7/2 times within the coating it will have the same effect. By adding multiple coating layers with different design wavelengths you can then achieve rather broadband absorption over a wide range of different wavelengths and tilting angles.
Not all filters are based on interference, but that Hoya one certainly is! On the other side of the equation I have some UV-bandpass filters that are based on interference as well, and some that are based on absorption. There are of course variations in coatings as you suggest - some are definitely better than others. The point of this experiment was more to illustrate that filters claiming to be UV-blocking are often not, and even when they are you'll encounter quirks to how they operate. Thanks for watching and providing your input here!
@@DonKomarechka You're absolutely right with the absorption based filter which I forgot to mention. I really enjoyed this video. Thanks for the great work.
Regarding the "off-axis" light...When thinking about the light entering our camera, we are 99% concerned with the UV from the sun. Those rays, for all practical purposes, will always be perpendicular to the lens face (because the sun is 93 million miles away). So when you use a point light source, like a flashlight, you are no longer a true comparison to the sun. UV lenses were specifically designed for the sun UV rays.
Sunlight isn't collimated but it has far less divergence than a flashlight, yes... but it's angle is always changing based on the angle of the camera and heck even the rotation of the earth. There are different types of UV filters, with the off-axis light changing caused from thin film interference effects - the filter uses optical interference to destroy specific wavelengths of light, but that is dependent on the angle. A more oblique ray of light passes through more of specific coatings, which in turn will change the interference pattern and create sub-optimal results. These interference filters often have subtle colour casts when looking at them, especially at odd angles. Other UV filters - those that generally appear optically clear from all angles - will use UV absorption as the method of removing the light. This can be done in a number of ways, some of which cause faint fluorescence of the glass itself. In real-world scenarios this wouldn't pose a significant impact on the images you create, but it's interesting to see it in a "laboratory" setting. Interesting to me, anyways! :)
They block UV very well! I shot a selfie with them on, using a camera modified to capture UV light directly and the exact same safety glasses were completely dark: twohosers.com/the-two-hosers-photo-show-354-dkuv/
I have been using Zeiss and B+W filters for decades and are great but very expensive. Hoya have various types of UV , ND or polarized filters. Some are cheap, some other are more expensive and better. You get what you pay. In general Hoya offers best value for money.
The Zeiss T* filter was USD$124 and the Hoya UV/IR cut filter was USD$108. Both not cheap (for a UV filter), but each using incredibly different ways of preventing UV light from entering the lens. Some cheap filters I have tested will outperform the more expensive ones, and some expensive filters have done nothing to block UV light even though they claim to. It's definitely an area of frustration, though thankfully it's easy to test like we did in this video. :)
Fourth.....? But seriously wanted to say great topic, using a converted camera for IR and UV photography. Great ideas to add and try thanks. Well done.
Thanks for enjoying! This doesn't require a converted camera by the way, since the UV light fluoresces back into the visible spectrum, and the camera then captures that visible light. :)
Hi Don, Would printer refill ink work just as well as the highlighter refills for the UV macro photography? Also any chance you can make a video of things to photography while were all stuck in isolation and the very basic camera tools?!
cool. fishbowl gave me an idea. there is a fresh water tropical fish, available in most aquarium stores, called a NEON TETRA. illuminate them for a while and they GLOW multi colors in the dark as they swim. Shine UV on them, as well as SR1 mega sensor as they transit the water, perhaps 10 of them. WOW. now that would be interesting.
Hah, using the fish for light painting - fish painting! Just don't put the UV inks in the water at the same time, I doubt that would be healthy for the fish. :)
@@DonKomarechka dude. light em up with some tungsten or incandescent then kill the lights...and roll. .they glow in the dark. multiple colors. no need inks. would make a cool desktop screen saver.....artsy fartsy luminence biological style. try aquarium store for bio lum brine shrimp too. long exposure, they move in trail patterns. very cool.
@@DonKomarechka ah ah ah. MY idea. credit to Marty Sender. you subscribe my channel? okay do fish. I'm okay with it. Marty Sender You Tube. I'm in DC area. I guess you is up there in Canada land in the middle somewhere where Chris and his video geeky nice guy live. Hey guys send me some demo lenses for my music vids. I'll rate and return.
@@DonKomarechka Hi ! I found Convoy S2 UV in local store. Is this flashlight is good for works like this ? I see you use another model, but with UV lamp i found just S2.
@@dima1353 it SHOULD work, but anyone can put that name on a product... not sure about consistency but yes! "Convoy" is the name that has garnered my respect. The S2+ I believe is an 6W device vs. 4W for the S2, and there is the C8 which is 8W from a variety of people as well. Buy two! :)
What type of UV protective eye glasses do you use? If some if the UV camera lens filters aren't all equal in quality in their ability to block UV, are all UV protective eye glasses equal in their quality to protect the eyes from such strong UV flashlights?
In the same way that you can test the effectiveness of a UV filter, you can put your glasses in the path of the UV light to see how much light passes through. Most of the time, even standard eye wear will block UV light very well - a quick search online will find a good selection of UV protective glasses for around $10 a pair. The irony is that most of these cheap plastic glasses are all effective at blocking UV light, whereas the lens filters are a mixed bag - because UV filtration of light into the camera is not so much of a problem compared to UV light damaging your eyes. The glasses we were wearing are about as effective as the Hoya UV/IR cut filter, but from every direction of light.
Hi Don, I love your job and I want to try something similar. I am going to buy the convoy s2+ torches but I have a question: do you use filter like hoya u-340 directly applied on the torches for cutting non uv light? Thanks.
For subjects that fluoresce very brightly, such as the minerals we were playing with or the fluorescing inks, the Convoy S2+ flashlights are perfectly fine. They do bleed a very small amount of visible light but this is inconsequential to the results here. If you were experimenting with very dim organic fluorescence, you could start with just the flashlights and filter down farther if needed. The flashlights already have a piece of ZWB2 glass in front, which works decently. :)
Awesome, I find Don to be very inspirational and loved the video. What is the model of the UV Flashlights? I would love getting into this type of photography, but I am unsure which Flashlights are most suited for it (produce strong UV light with no visible light). Thanks for any help!
The flashlights are the Convoy S2+ and Convoy C8 Fyrfly. The latter has a more intense, condensed beam and the former is a little wider. Both are great!
@@psyysp171 my pleasure! I might start with two Convoy S2+ flashlights just so that you can have one on each side for more even lighting. We used four, but you don't need that many. Since these images are more abstract shapes, they survive noise reduction very well if needed. Happy shooting! (oh, and remember the UV safety glasses!)
I was shooting with the Lumix S1R and the Canon MP-E 65mm lens, while Chris (I think!) was shooting with the Lumix GH5 and the Lumix 30mm macro - a great combination!
And relating to the UV filter in front of the sensor: Almost all sensors have micro lens arrays in front of them to maximize light throughput. However, they only work effectively if the light rays from the camera lens do not fall in to oblique. If the light rays come in too steep you will start to see color casting on the edges of the image (best example: Leica M9 with non-corrected 21 mm wide angle lenses). Modern lens designs for digital thereby limit the range of incident angles to avoid these problems. Therefore, the UV filter on the sensor has much looser specifications regarding incident angles and will thus perform better than the filters you attach to your lens.
You're right about the microlenses, I remember reading a whitepaper about how CMOS sensors suffer from this light detection from extreme angles, thus needing something to help refocus the light for better detection. That said, by the time light has reached the general area of the sensor it is much more directional than the light before it enters the lens, making such interference filters in front of the sensor (some manufacturers have separate filters for UV and IR) less prone to off-angle issues. Still, if a lens was designed in the film era and is generally of a wider focal length, you'll see more of an issue like you've described with the M9. I have a 17mm Vivitar Series 1 FD mount lens that exhibits the same. I also see colour casts around the borders of the frame when using a full-spectrum camera narrowed down to only UV with a 77mm filter, because the filter uses optical interference and it's effectiveness varies over the larger size. Definitely a lot to dig into here!
Don is always such a great guest. You never feel stupid when he explains his ideas and point of views
It was interesting how much better Don's photos were, shows how much experience and practice counts for this stuff.
Interference filters are working with destructive interference. That is, they are made of many thin coats (sometimes as much as 30). The thickness of the coats are calculated such that reflection between each coat destructively interfere with each other at a given wavelenght hence the filtering effect. When you tilt the filter the distance the light travel is now longer and the effect disappears.
These are typically great filters and can be very specific. Astronomy if full of them.
Trivia: multiple of the wavelenghts will also be filtered. Usually that doesn't matter because it's not in the visible.
en.wikipedia.org/wiki/Interference_filter
And this is exactly how the coatings work on our lenses - at least, most of them. It's easy to see how the filters are only applicable in certain wavelengths by shooting an infrared image with the sun in the frame - massive flare because the interference coatings were designed with the visible spectrum in mind (even though, as you mention, there are interference coatings for many wavelengths, often used when shooting astronomy-related subjects)
These interference coatings are also how sensors block UV and IR light, typically, but they are more effective on the sensor because the light is coming from a more direct angle. Using such interference coatings on a UV filter at the 77mm size is less effective than using an absorption filter - but they too can have issues (some of them like the Zeiss T* UV will faintly fluoresce).
That little segment of the video was mainly just to bring to light that there's a lot of different ways to do this, but more importantly that some manufacturers flat out lie about the capabilities of the filters and different filters - even good, expensive ones - will behave differently. :)
Hope you enjoyed the video!
@@DonKomarechka The quality and wave length of the filters is determined by the number of layers and the type of coating.
If you have interference filters in the visible (say like the H-alpha) and you tilt them you can immediately see with your eyes the same phenomenon of the filter color shifting. See www.baader-planetarium.com/en/baader-h-alpha-7nm-ccd-narrowband-filter.html
It never occurred to me that it would be an issue in regular photography. But it is worst here because it occurs at wavelengths we cannot see.
Good to know. Thanks
@@patricescattolin43 Baader makes some exceptional filters, I have their U-Venus filter and I wish they made it in bigger sizes... but it doesn't suit the intended application. The larger the filter, the more likely you'll have oblique angles to light, so this makes sense that the purpose and diameter have constraints. We're pushing the limits! :)
@@DonKomarechka BTW it's possible that this is the reason that most of the UV light filters didn't block the specific wavelength of the UV flashlights. The UV you have to deal with from the sun might be a different wavelength and that is what those filters are designed for. You'd have to test them in sunlight with a UV camera.
I'm just speculating though.
@@dejayrezme8617 Unless I'm very much mistaken, the sun emits ALL wavelengths.
This is fantastic. One of those examples that Don comes up with so often of how anyone can experiment and create unique images fairly easily and inexpensively. This one is bookmarked so I c can reference it later. Thanks!
Thanks so much for the kind words, Steve!
I love photographing with UV! Glad to see some amazing photos from this session!
Is this where dreams come from? Thanks for the video DPReview!
Don: I'm just priming the pipette for you...
Chris: *bashful* DoNnnnn...
hahahaha
Now I remember why I am following Don on Instagram. Thank you Chris!
Love Don, great episode guys. There are some awesome and unique shots there. A very creative way to use common objects to create stunning images. Thanks guys!
I wish he would have tested his glasses to see if they actually block UV, after he tested the filters.
Oh, they do! I shot a selfie with them on, using a camera modified to capture UV light directly and the exact same safety glasses were completely dark: twohosers.com/the-two-hosers-photo-show-354-dkuv/
@@DonKomarechka Cool! What model of safety glasses did you use for the experiment?
@@lawtonc8900 just some generic ones from Amazon. Tested them in the same way we did the filters to know they were effective. :)
Great video! Didn't realize about UV photography and how unique it is!
More photographers needing glasses... The plot thickens.
Haha! “Photographers” 🤓
Wow. I thought it was kinda cool at first, but when I saw the flower it raised my eyebrows, then when he dropped the ink onto it my jaw dropped.
Don is amazing, I've been following him on Instagram since the last video, and he takes very cool pictures (also making it look easy)
Magnific!
You guys could make a video about shuttercount and life of a camera, would be very nice
this guy is awesome, please do more vidoes with him
Even changing the temperature of the water gives you new designs,... try it.
Oh its a lot of fun, getting some convection started in the tank with a heat gun or blow dryer adds some very interesting effects!
Try adding some ice cubes.
@@skakdosmer I had tried that for one of my initial experiments in studio Lau, interesting results! We didn't have ice cubes when we were recording this video though. I even thought it would be interesting to place the aquarium on a slab of dry ice, or somehow supercool the tank below the freezing point and then use even colder inks which would cause a nucleation event that would cascade the entire tank into freezing. Might not make for a great image, but it would be all sorts of fun!
Great video Don. very informative
Very cool, this has me excited to try this out! I've been wanting some good UV lights for a while so I appreciate the brand recommendation. Is there such a thing as *too* much UV flashlights?
Awesome!!!!!!!
Nice art photography
Super cool, Don is very inspirational.
Thanks for sharing, it's an interesting video. One small comment: it would be helpful, during the demonstration of the effectiveness (or lack thereof) of the UV filters, to move the filters in and out of the range of the UV light to show the colour of the light with and without the filter. Also helpful would be to do this interchangeably, in one take, with an effective UV filter and ineffective one for comparison. This is very minor, but IMO would make the point way more convincing.
Good point! However, this wasn't meant as a comprehensive review of every UV filter available, just showcasing a few with quirks to illustrate the point that many of them are made differently. We'd have to build transmission charts to really do it right, and I believe there is a LensRentals blog post that covered that in the past - and even that doesn't take into account for off-axis light and fluorescence of the filter. Still, you're right, swapping a good vs. bad filter in one take would be a good visual. :)
Very cool video, basically a professional version of stuff that I experimented with some months ago. I also noticed that cheap UV flash lights are bleeding a lot of visible light and that my UV filters are really not filtering UV at all. My plan was to use the same Noodler's uv ink that is used in the video, but I was to water my flowers with it to make them more fluerescent (just like you sometimes see people dye roses with colored water). I can report that this plan did not work at all and my flowers died within a few days :(
Apparently feeding invisible ink to flowers is unhealthy. In some of my early experiments I tried the same thing! I have wanted to revisit the concept with diluted ink and plant food in the mix to see if it helps, focusing on buds rather than already blossomed flowers to have a larger impact. There's always more to experiment with.
@@DonKomarechka I already diluted the ink quite a bit, probably 1:100 or so.
@@terriplays1726 then the next step would be make a solution with fluorescein. I have some fluorescein strips used by optometrists to detect problems with eyes or to fit contact lenses. It fluoresces a yellow-green colour and is biologically inert. Just too many things on my to-do list. :)
To the question why there is an angle dependent transmission and some filters perform better than others:
All these filters are based on destructive interference, meaning that the thickness of the coating is specially designed so that the wavelength of choice cancels itself out. This is performed by overlaying a light wave that is purely transmitted with one that is first reflected at one coating surface, then back-reflected from the next coating surface to then finally exit the filter as the first wave did. If the distance difference between both is exactly half the wavelength, the addition of both waves will lead to zero amplitude. This is why coatings are very thin as the wavelength of visible light is around 100 times smaller than a human hair. When you tilt the filter the light is travelling a longer path and so the path difference between both beams doesn't match half the wavelength anymore.
As one thin coating layer only targets a single path difference perfectly, any other wavelength will be transmitted as was shown for the cheap filter. This also holds true for filter tilting. More expensive filters, however, use the tricks of using multiple and thicker coatings. First, thicker coatings are designed to cancel out a wavelength that is much longer than the original one. However, if the original wave travels 3/2 or 5/2 or 7/2 times within the coating it will have the same effect. By adding multiple coating layers with different design wavelengths you can then achieve rather broadband absorption over a wide range of different wavelengths and tilting angles.
Not all filters are based on interference, but that Hoya one certainly is! On the other side of the equation I have some UV-bandpass filters that are based on interference as well, and some that are based on absorption. There are of course variations in coatings as you suggest - some are definitely better than others. The point of this experiment was more to illustrate that filters claiming to be UV-blocking are often not, and even when they are you'll encounter quirks to how they operate.
Thanks for watching and providing your input here!
@@DonKomarechka You're absolutely right with the absorption based filter which I forgot to mention. I really enjoyed this video. Thanks for the great work.
Inspiring. Thank you!
Regarding the "off-axis" light...When thinking about the light entering our camera, we are 99% concerned with the UV from the sun. Those rays, for all practical purposes, will always be perpendicular to the lens face (because the sun is 93 million miles away). So when you use a point light source, like a flashlight, you are no longer a true comparison to the sun. UV lenses were specifically designed for the sun UV rays.
Sunlight isn't collimated but it has far less divergence than a flashlight, yes... but it's angle is always changing based on the angle of the camera and heck even the rotation of the earth. There are different types of UV filters, with the off-axis light changing caused from thin film interference effects - the filter uses optical interference to destroy specific wavelengths of light, but that is dependent on the angle. A more oblique ray of light passes through more of specific coatings, which in turn will change the interference pattern and create sub-optimal results. These interference filters often have subtle colour casts when looking at them, especially at odd angles.
Other UV filters - those that generally appear optically clear from all angles - will use UV absorption as the method of removing the light. This can be done in a number of ways, some of which cause faint fluorescence of the glass itself. In real-world scenarios this wouldn't pose a significant impact on the images you create, but it's interesting to see it in a "laboratory" setting. Interesting to me, anyways! :)
You should have tested how much UV passes through the safety glasses while you were at it.
They block UV very well! I shot a selfie with them on, using a camera modified to capture UV light directly and the exact same safety glasses were completely dark: twohosers.com/the-two-hosers-photo-show-354-dkuv/
Speaking of weird liquids - will there be an end of the year episode with the team this year?
Yes!
Jordan @ DPReview TV
Very interesting! Thanks!
I have been using Zeiss and B+W filters for decades and are great but very expensive. Hoya have various types of UV , ND or polarized filters. Some are cheap, some other are more expensive and better. You get what you pay. In general Hoya offers best value for money.
The Zeiss T* filter was USD$124 and the Hoya UV/IR cut filter was USD$108. Both not cheap (for a UV filter), but each using incredibly different ways of preventing UV light from entering the lens. Some cheap filters I have tested will outperform the more expensive ones, and some expensive filters have done nothing to block UV light even though they claim to. It's definitely an area of frustration, though thankfully it's easy to test like we did in this video. :)
Don Komarechka Thank you for the informations.
Oh thanks, Guys, another imaging obsession to investigate.😎
You're welcome, have fun with it! :D
well that video was refreshing!
Fourth.....? But seriously wanted to say great topic, using a converted camera for IR and UV photography. Great ideas to add and try thanks. Well done.
Thanks for enjoying! This doesn't require a converted camera by the way, since the UV light fluoresces back into the visible spectrum, and the camera then captures that visible light. :)
Hi Don, Would printer refill ink work just as well as the highlighter refills for the UV macro photography?
Also any chance you can make a video of things to photography while were all stuck in isolation and the very basic camera tools?!
Great video, thx ! :)
Bright idea
Hi Don
Where did you buy the uv-light?
cool. fishbowl gave me an idea. there is a fresh water tropical fish, available in most aquarium stores, called a NEON TETRA. illuminate them for a while and they GLOW multi colors in the dark as they swim. Shine UV on them, as well as SR1 mega sensor as they transit the water, perhaps 10 of them. WOW. now that would be interesting.
Hah, using the fish for light painting - fish painting! Just don't put the UV inks in the water at the same time, I doubt that would be healthy for the fish. :)
@@DonKomarechka dude. light em up with some tungsten or incandescent then kill the lights...and roll. .they glow in the dark. multiple colors. no need inks. would make a cool desktop screen saver.....artsy fartsy luminence biological style. try aquarium store for bio lum brine shrimp too. long exposure, they move in trail patterns. very cool.
@@martysender5539 This is now on my to-do list!.... after I finish my book. :)
@@DonKomarechka ah ah ah. MY idea. credit to Marty Sender. you subscribe my channel? okay do fish. I'm okay with it. Marty Sender You Tube. I'm in DC area. I guess you is
up there in Canada land in the middle somewhere where Chris and his video geeky nice guy live. Hey guys send me some demo lenses for my music vids. I'll rate and return.
Now thats a great inspirational video
Than u
What wavelength UV is the flashlight emitting UVa or UVb? Many objects need UVb light to fluoresce.
These flashlights are longwave UV with a peak around 365nm
@@DonKomarechka Hi ! I found Convoy S2 UV in local store. Is this flashlight is good for works like this ? I see you use another model, but with UV lamp i found just S2.
@@dima1353 it SHOULD work, but anyone can put that name on a product... not sure about consistency but yes! "Convoy" is the name that has garnered my respect. The S2+ I believe is an 6W device vs. 4W for the S2, and there is the C8 which is 8W from a variety of people as well.
Buy two! :)
@@DonKomarechka Thank you.
What type of UV protective eye glasses do you use?
If some if the UV camera lens filters aren't all equal in quality in their ability to block UV, are all UV protective eye glasses equal in their quality to protect the eyes from such strong UV flashlights?
In the same way that you can test the effectiveness of a UV filter, you can put your glasses in the path of the UV light to see how much light passes through. Most of the time, even standard eye wear will block UV light very well - a quick search online will find a good selection of UV protective glasses for around $10 a pair. The irony is that most of these cheap plastic glasses are all effective at blocking UV light, whereas the lens filters are a mixed bag - because UV filtration of light into the camera is not so much of a problem compared to UV light damaging your eyes. The glasses we were wearing are about as effective as the Hoya UV/IR cut filter, but from every direction of light.
Hi Don, I love your job and I want to try something similar. I am going to buy the convoy s2+ torches but I have a question: do you use filter like hoya u-340 directly applied on the torches for cutting non uv light? Thanks.
For subjects that fluoresce very brightly, such as the minerals we were playing with or the fluorescing inks, the Convoy S2+ flashlights are perfectly fine. They do bleed a very small amount of visible light but this is inconsequential to the results here. If you were experimenting with very dim organic fluorescence, you could start with just the flashlights and filter down farther if needed. The flashlights already have a piece of ZWB2 glass in front, which works decently. :)
Glad to know that comments are not turned off lol
Awesome, I find Don to be very inspirational and loved the video.
What is the model of the UV Flashlights? I would love getting into this type of photography, but I am unsure which Flashlights are most suited for it (produce strong UV light with no visible light). Thanks for any help!
The flashlights are the Convoy S2+ and Convoy C8 Fyrfly. The latter has a more intense, condensed beam and the former is a little wider. Both are great!
@@DonKomarechka thanks a lot! Do you need multiple flashlights to get decent images, or is it possible to start out with just one?
@@psyysp171 my pleasure! I might start with two Convoy S2+ flashlights just so that you can have one on each side for more even lighting. We used four, but you don't need that many. Since these images are more abstract shapes, they survive noise reduction very well if needed. Happy shooting! (oh, and remember the UV safety glasses!)
It would be nice if we were informed about the lens and the camera that was used.
I was shooting with the Lumix S1R and the Canon MP-E 65mm lens, while Chris (I think!) was shooting with the Lumix GH5 and the Lumix 30mm macro - a great combination!
..Don... !? 😂
And relating to the UV filter in front of the sensor: Almost all sensors have micro lens arrays in front of them to maximize light throughput. However, they only work effectively if the light rays from the camera lens do not fall in to oblique. If the light rays come in too steep you will start to see color casting on the edges of the image (best example: Leica M9 with non-corrected 21 mm wide angle lenses). Modern lens designs for digital thereby limit the range of incident angles to avoid these problems. Therefore, the UV filter on the sensor has much looser specifications regarding incident angles and will thus perform better than the filters you attach to your lens.
You're right about the microlenses, I remember reading a whitepaper about how CMOS sensors suffer from this light detection from extreme angles, thus needing something to help refocus the light for better detection. That said, by the time light has reached the general area of the sensor it is much more directional than the light before it enters the lens, making such interference filters in front of the sensor (some manufacturers have separate filters for UV and IR) less prone to off-angle issues.
Still, if a lens was designed in the film era and is generally of a wider focal length, you'll see more of an issue like you've described with the M9. I have a 17mm Vivitar Series 1 FD mount lens that exhibits the same. I also see colour casts around the borders of the frame when using a full-spectrum camera narrowed down to only UV with a 77mm filter, because the filter uses optical interference and it's effectiveness varies over the larger size. Definitely a lot to dig into here!
ps have you tried black light paint and a black light? whoa. endless possibilities. Marty Sender You Tube
crap
First?