I accidentally had one of these lenses stored under my bed for 2 years attached to an old camera my father in law gave me. I've removed it now of course and bought a GMC 320+ Geiger counter to check out the beta and gamma coming out the thing. I'm getting over 1000 pcm at the back of the lens, but thankfully only 34pcm average when the lens is on the camera and in the camera bag, and 25pcm where I was laying in bed with the camera bag underneath. background levels average about 17pcm. Bit of a relief considering it was only a foot away from my balls for 7 hours a night for two years lol
I bought the same Geiger Counter. I have 3 vintage Takumar lenses that are radioactive. None read as high as this guy's lens. Three of my Takumar lenses are radioactive. One is 1550 CPM and the other 760 CPM. All on the back lens. My Super Takumar read 2250 CPM on the back lens. The rest of my vintage Takumar and FUJINON lenses have no CPM activity. I bought these because they were radioactive. They are classic vintage lenses. The CPMs really drop off fast as you move away from the lens. At 2 inches with the cap off the back lens, the reading in around 165 CPM. With the lens caps on and in an Olympus camera case I get about 100 CPM.
Nope, has nothing to do. Probably only add more noise to the picture. ISO is just how sensible is the sensor to the light that gets in, when there's no other alternative to opening the aperture (the hole) wider to let more light in, or let the sensor get more light (longer exposure), higher ISO at the cost of noise and weird purple/blueish spots.
Kodak had some problems when the US began testing atomic weapons. Stored and unexposed film was getting ruined with mysterious spots. There is a cool documentary about it.
A long time ago (35+ years) I was an industrial chemist. The company I worked for made, among other things, various radioactive compounds (with a license from the NRC). One of the things I made on a continuous basis was Thorium Flouride. It was used by the camera optics industry, but not as an ingredient IN the glass (as in your exampke), but as an anti-reflective coating ON the lens. It was vapor deposited on the lens surface in a layer that was only a few molecules thick. I was told at the time that with a layer that thin, the amount of radiation from the (tiny) quantity of Thorium present on a single lens was nearly impossible to detect. (Of course, since I was making kilograms of the stuff at a time we had lots of radiation monitoring going on!)
Thoriated glass has great optical properties but it is a little radioactive. After many years Thoriated glass gets a yellow tint due to the radio decay.
Many of these lenses with thorium oxide elements have insanely good optical qualities, especially for when they were made. Elements with thorium oxide(up to 30% by weight) have high refractivity and low dispersion, which helps reduce chromatic abberations as well as facilitating the use of less curved elements which are easier to manufacture. Very similar technology is still being used today. Canon's very high end L-series lenses, especially the telephoto ones with white barrels, use fluorite elements. Fluorite elements have a crystaline structure that is almost identical to that of thorium oxide, thus giving fluorite glass the same properties as thorium oxide glass. The use of thoriated elements has pretty much entirely stopped with the advent of the newer types of ED glass, many of which compensate for abberations better than fluorite or thoriated glass. I personally own a Super Takumar 50mm 1.4 in m42 screwmount from 1962 that uses thoriated elements, and it is easily the best lens I own in terms of image quality. It honestly does a better job than many of my much more modern lenses, both on film and on digital.
VicariousReality7 ED just means extra low dispersion glass. There are many types of ED/ Low dispersion glass, including Fluorophosphate glass. Most modern types of low dispersion glass are just trying to get the benefits(and physical/optical properties) of thoriated or fluorite glass without any of the disadvantages, like fluorite's weakness and heat sensitivity or thorium oxide's radioactivity. In the end they accomplish pretty much the same thing, the reduction(or outright removal, in the case of superachromat lenses) of optical abberations.
As Michele said, not very. The actual gamma dose rate to your head while using a lense like this is very low, especially when compared to cruising at 35,000ft. The LND7317 geiger tube in the Inspector USB is a very sensitive tube, especially to the large number of beta particles coming from the lense, which geiger tubes - especially ones with thin mica windows like the LND7317 - are excellent at picking up, so the lense sounds very active indeed! But what you have to remember is that these practices are mostly blocked by the body of camera and have very low penetrative power. You would receive a dose my orders of magnitude higher than this from a simple X-ray. That being said, if you're stupid enough to stick this thing to your eye ball then, yes, it can have a detrimental effect to your beta sensitive eye lense...given enough time.
@@lanchanoinguyen2914 The science and statistics would suggest that you need to be far more concerned about the air you breath walking around a city than you should be about the very small amount of time spent holding this lense! Everything is relative... I'm exposed to doses FAR in excess of this for my own professional nuclear research work, and yet the doses I'm allowed to be exposed to on a daily basis (full body doses no less) are still insignificant when compared to just a few minutes spent at hospital in a C/T scanner. You really need to run the numbers...if you're concerned about the risk from this lense, then you are woefully ill-informed of the day-to-day risks associated with life as we know it, and to the physics of the interactions between matter and radiation. Please do your research. Thank you.
This surprised me that at the time when the lens were being used there wasn't a huge health advisory sent out. It could be extremely dangerous if the lens were broken or even worse shattered.
older lenses like Leica, particularly from the late fifties and sixties came with a radioactive brush to wipe a cross the lens to get the dust off of it.
Plastic blocks most alpha partials from these lenses. Plexiglass in fact. I just bought a Olympus OM-System G.Zuiko Auto-S 55mm f1.2 1974 Radioactive 3389 CPM lens. It is hot. More on the front lens than the back. Back is 950 CPM. The front is 3389 CPM. After reading this paper on the use of plastic to block the Alpha partials I stacked four 0.25 blocks of plexi on the front of the lens. Using GQ GMC 320 Plus I was able to measure a drop from 3389 CPM to 540 CPM. Just think about what 2 inches of plastic would do. Now that is news.
I have a GMC 320+ Geiger Counter. I have 3 vintage Takumar lenses that are radioactive. None read as high as this guy's lens/counter. Three of my Takumar lenses are radioactive. One is 1550 CPM and the other 760 CPM. All on the back lens. My Super Takumar read 2250 CPM on the back lens. The rest of my vintage Takumar and FUJINON lenses have no CPM activity. I bought these because they were radioactive. They are classic vintage lenses. The CPMs really drop off fast as you move away from the lens. At 2 inches with the cap off the back lens, the reading in around 165 CPM. With the lens caps on and in an Olympus camera case I get about 100 CPM.
Thorium compounds, and isotopes. Fun stuff! Asahi was originally a rubber company, and made the rubberized silk shutters for the old K1000 series Pentax cameras. Now Ashi is supposedly an optics coatings company. We also use thoriated tungsten in transmitting vacuum tubes. Lots of camera lenses have heavy thorium in the glass. The rubberized silk shutters are really incredibly robust, especially compared to the ME era metal fan type shutters. Those tended to warp, and they won't fully set or reset. The rubberized silk just does it's thing, and it does it very well. I loved the ME Super, and Super Program Pentax. Small, smart, semi automatic, and just loads of fun.
These lens are supposed to have a yellow hue. These lenses with thoriated glass provide excellent contrast and tone. Made in the 1970's the lenses like this with doped thorium glass were expensive and VERY good. I think these lenses are only really dangerous if you swallowed it!
It's interesting how unlike our eyes, digital cameras CAN indeed detect gamma rays (as well as x-rays) at very high intensities though I don't know why they appear as dots rather than light as they should but I'm guessing the dotted effect is due to the fact that most of the photons just go straight through the camera's CCD. I wonder would putting those lens up to a digital camera give you that cool effect; I've seen someone get that effect just by placing pitchblende ore up to a digital camera.
Hmmm... This lens is for film SLR camera. I wonder how much it causes fogging of the film due to radioactivity? Especially for long time not moving film to the next position and/or for long exposure.
Got one of these on order. So not only will it be great for photography, but also a nice test source for my Geiger counters. I may or may not do the UV treatment thing. I will take some shots and then decide.
aj ledezma You got it. May I ask how you know? The alcoholic beverage industry in the US got a law passed requiring alcoholic beverages form human consumption to be radioactive. (Oil companies could make high quality alcohol very inexpensively from oil.) If alcohol is radioactive it means it came from something which was recently living. I was told just a few years ago the US seized a containers of wine from Italy because the wine was not radioactive. (It was made from oil.)
Passed High School Physics WTF I think this is a result of that stupid Mith about everything being ion-radiating, when only some elements and isotopes are. My dad: don't drink that chemicals it is radioactive Me: it is carbonated water My dad: then why does it say carbonic acid. Me: because it is its chemical name My dad: *confiscates H2CO3* Me: ok I'll just drink hydrogen Oxide. My dad: no that's poisonous. Me: it's water. Ok I'll just have some sour salt for snack. My dad: it says citric acid it must be radioactive. Me: ok I'll just drink a sodium hypochlorite solution because you won't let me drink water. My dad: ok I'll have double You know what happened next
When switching to the front lens the count is lessened because the distance to the source has increased several times; not so much that the front element is blocking the radiation. In the examples of radioactive camera lens I've seen, the radiation always comes from the rear element only. I've taken elements out of the housings and also found that the radiating piece of glass is more intense on one side than the other. That suggests that it is the coating rather than the entire glass that contains Thorium --- the radioactive isotope. This is contrary to the literature I've seen which claims that the entire glass is doped up to a third of its weight.
Actually I do not think the lens will be "pointing directly at your eyeball" when you open the shutter to take an exposure. You will still have the pressure plate, usually metal, and the back of the camera body. I don't know though what effect this would have on blocking the different radiations. What about distance? How much would your reading decrease if you moved back 1 inch, 2 inches , etc.?
The change in reading with respect to distance is governed by Distance Inverse Square. Intensity at point B from point A: B = A/(4πr^2) where r=distance. So, for a unit squared, perhaps 1 inch squared, the change in intensity is: Inches Intensity 0 1 1 0.0796 2 0.0199 3 0.0088 4 0.0050 10 0.000796 100 7.9578×10^-6 Distance inverse square.
Can anyone help me out with this? I have the Nikon NIKKOR-Q 135mm f2.8 NON-Ai lens & I am wanting to know if this lens is Radioactive in any way? Any help would be greatly appreciated!
put the lens to the sun to remive the yellowing. i checked mine, 0,5 mR/h x100 that means 50mR/hr. Used on the camera, probe on the back of a pentax spotmatic i read 0,2mR/hour at x1 so no big deal to use it.
I wouldn't worry about the radiation from these camera lenses. It sounds scary on a Geiger-Müller counter close-up, but in reality, it's not much. And the glass attenuates some of the radiation, too. Thorium-232 has a half-life of over 14 billion years, making it weakly radioactive. Its decay progeny has shorter-lived radionuclides, thus more they're more radioactive, but it's still not much. And they are nice lenses.
+Spock Some, yes. (I had the same thought). The reasons it makes little effect are: 1. Higher energy photons from ionizing radiation have a high chance of simply passing through the film and not depositing energy in it. 2. The actual intensity is low (photons/s). Millions of times less than light. 3. The film is more sensitive to the visible spectrum, most of the time. But given a really long time I suppose it would.
+antiprotons isn't cause of cancer only related to statistics in this situation? could single radiation source of this kind of takumar lens cause cancer cells? hwo about immune system? i love MF lenses but i choose not to keep takumars. they are very good at micro contrast and have very low CA., but no thanks.
maybe if you left a roll of unexposed film wound in the camera over 10 years with the lens on.... in a freezer to prevent emulsion damage from time/heat.
In day to day usage, will the lens harm me? I use it for portraits. It's not like I cuddle with the lens every night but I do always carry it with me. What will the radiation actually do to my body that my cell phone in my pocket isn't already doing ?!
Perhaps they have. I don't know of any good research done in that field. Having the lens close to your eyes for hours at a time or handling broken lenses are likely the only two ways to be affected by one of these (though, technically any dose of radiation increases your risk of cancer). I used to be a photographer, but none of my lenses were hot. :)
Since the cameras used are/were largely if not completely metal I would guess that gives at least some protection. The back of the camera is certainly metal. The shutters in Pentaxes these lenses were used on I think were fabric although some other SLR shutters were metal. When the photographer is using the camera he is looking through the lens via two optical reflections, the mirror behind the lens and the pentaprism. I don't know if the mirror has metal on the back of it or not. Perhaps the greater reading from the back may be due to the rear element being the culprit? I would guess the lens has from 5 to 7 different glass elements, possibly of different glass formulations. If the radiation is coming from the rear glass would some of the intervening glass when measured from the front or the short increased distance decrease the reading?
***** There are two things in play: The beta and alpha from the glass, which are blocked by the casing at glass easily, and the gamma/x-rays from the glass. The gamma and x-rays will pass through the lens as though it were not there. The metal will only shave a few % off of the gammas. My scintillator gets a nearly uniform reading, but my alpha/beta/gamma sensitive Geiger counter has vastly different readings due to the glass.
antiprotons You were getting vastly different readings between the back and the front with both devices, weren't you? Doesn't that imply the culprit is the rear element? Is the lower reading from the front due to distance? Does the radiation follow the inverse square law and IF the radiation was coming from the rear element it would be greatly less even a slight distance away?
***** You have several things in play: Change in intensity with respect to distance. Change in intensity with respect to attenuation. Change in intensity from intervening objects. All of these reduce the reading. I suspect the back is the culprit.
The brown discoloration often seen on this type of lenses is easily removed with a small and inexpensive LED desk light from Ikea. Place the lens without the caps on a mirror. Position the LED head about an inch above it. Let it shine, let it shine, Let it shine. Occasionally turn over the lens for even exposure. Takes a day or 2. NEVER leave a lens in the sun. The lubrication will melt and you end up with sticky aperture blades.
Although i don´t believe this radiation can cause severe damage i am pretty much surprised! I wonder if i need a lead protected case for my own lens collection...
In fact staying up late to remove the yellow cast from the radioactive element probably kills my health more... I have two Pentax lenses that are radioactive, and they take excellent pictures, except removing the yellow cast is pretty hard.
No idea, but I would suspect that they were exposed to quite a lot. The workers who made all of this radioactive stuff are often ignored. Here is a neat video showing how thorium was extracted and processed in India. It's creepy to watch the workers handling all of it: Atomic Fuel India
antiprotons My grand parent's old off-the-grid place used propane lanterns for lighting with... thorium mantles. No doubt everyone there, myself included, inhaled/ingested bits of thorium oxide dust :D
I'm not sure if you've done any research on this, but many people have found that exposing the rear element to various types of light sources seems to reverse the yellowing process. Any idea what process is happening to cause that?
different lens elements can be made of radioactive glass due to its optical properties (chromatic dispersion, refractive index) that is why backi of lens radiates
Hallo! Thanks for the video. I have got an SMC Pentax 50 1.4 (not the Takumar) for years and its lenses don't seem yellowish but on the other hand I'd like to know if they are all radioactive or if is there at least a kind of serial index to determine if an SMC-M Pentax 50mm f1.4 is or not radioactive. Does anyone know anything about? Thank you
thank you so much for this video and for all the insightful comments below. it has really helped put the photography community at ease. i'm still curious about one thing.. if the rumor is true that leaving a thorium lens in sunlight for three days makes the yellow go away, how does the uv react to thorium in such a way and how long before the yellow returns? thank you again.
Do gamma rays bounce through lenses the way visible light does? Well, not exactly the same, they'd suffer a lot of chromatic aberration. What about other ionizing radiation?
Higher energy photons, like gammas, tend to go right through most matter. Lower energy photons, like light, sort of "splash" off of material, bouncing here and there. To a gamma, the camera lens is nearly transparent. This is the same for x-rays and beta's. Alpha's cannot penetrate more than a few micro meters of the metal.
I just tested Rokkor PF 1.4 with GMC 300E+ bought on Amazon, and the background radiation is about 0.1 MicroSv/hour. The GM counts about 18 average through apartment. At Rokkor PF it doesn't change but this is GM of a 100$ and it doesn't count alpha. What is your opinion, about measurements. Do I have to go further buying Alpha detector or this is enough to conclude measurements and happily use Rokkor 1.4. Thank you very much.
stickom I would not personally be that worried about the radiation from a single lens. The alpha counts make them seem pretty hot, but in the scheme of things they are actually pretty low level. Beta and gamma from a thorium lens are not particularly intense most of the time, which is why your Geiger counter isn't picking them up.
Two things I would like to have seen: 1. Do your geiger counter reading through one layer of aluminum foil. That's just for curiosity. and 2. Do your reading through a thin sheet of steel to simulate the back of a typical (Pentax) camera. The back of the lens is hotter than the front, but in actual use you would rarely be directly exposed to it. And, out of my field here, but I don't think the viewing system of the camera will refract/focus radioactive particles, so your eye is pretty safe, even at the instant of exposure. In fact, it would be interesting to do the whole Geiger counter part of the test on a lens mounted on a camera, as it would be in use. Measure with the camera at rest (shutter closed) and fire the shutter on "Bulb" or "Time" and see if any more radiation comes through.
I just looked up the half life of Thorium 232. It is 14050000000 years, and it emits alpha particles as it decays. I don't think that you would measure a lot of counts from glass containing a small percentage of that isotope. Are you sure about your spectroscopy?
Just bought a Pentax Spotmatic with one of these lenses on it. Great presentation. The current mythology on these lenses is that if you expose the lens to direcvt sunlight for a few hours/weeks/months (depending on which blog you read) the yellow will disappear. But if the radiation is bcausing the yellowing, and presuambly the lens will be radioactive far after we are all gone, that seems unlikely, don' don"t you think?
Hey, great videos. I read some of your explanations below. I'm curious at what point would the radiation levels coming off a sample would cause you concern? In uSv/hr.
Well, concern relates to risk and concern over risk... so this is more of a question of when I would be worried. If my sample had a dose rate of more than perhaps 1 uSv/hr at 1 meter (above background), I would not want to keep it. That is still very low, but beyond what I would be comfortable owning. I could not want to approach anything above around 100 uSv/hr at one meter, for more than a few minutes.
I have the Konica 57mm F1.2 which is also radioactive. It's a fantastic lens but does have the yellowing as well. Simply add some blue in photoshop to counteract the yellow and you're fine. Also, I don't worry about the radiation at all because you'll get much more radiation flying in a plane than you'd ever get from using a camera lens. People hear an item is radioactive and immediately fear it without knowing that you're bombarded by radiation every day just waking outside.
+mavfan1 The Thorium leaves a yellow-brownish cast on the glass after a few years. You can rid the glass of that coloration by exposing the lens to U/V light for 30-40 hours. I've heard of success just leaving the lens outdoors for a few days. The lens clears up all by itself.
+Speedyjens of course, but you don't get big amounts from using the lens, it's small amounts over a short time vs. small amounts over a long time in a plane, which is worse.
Hello, I wanted to ask you how you are with the spectrometer "Gamma Spectacular" Gs 1000 ... !! And 'good .....! ?? You've heard of the Theremino .... !!! ???? Hello Mirco
I am not sure but I completely understand your question. I really like the gamma spectacular but I use it with PRA 8. I did not really have much success with Thermino. Normally, I use my UCS 30 from spectrum techniques, but I find that the gamma spectacular is very useful in the field. It small and portable and works from my laptop without any trouble. The UCS 30 requires higher voltage and is more of a laboratory equipment.
+Chihaya Komatsu What is that even supposed to mean? Asahi is a single company, not the art. I shot canon (as well as a Wardflex TLR 120mm and Ricoh). Back in the early 90's we didn't have access to the web like we do today so it was possible to not know about something in utter detail.
They seem like a good idea, to me. I believe we need to get Fusion working. Lockheed Martin's Skunk Works says they will have a working prototype for commercial use in 5 years. We shall see. www.lockheedmartin.com/us/products/compact-fusion.html The LFTR design is much better looking than our current BWR and PWR's. They are likely safer, easier to maintain, and can be used to get rid of some nasty existing materials. The idea of having a coolant/fuel mixture is also impressive. I do worry that countries may use such devices to created weaponized Np237 devices, but what can you do?
Very nice! And it's relatively safe too! It's one of the few commercial products that is radioactive that I don't own . . . yet. But, I do have ThO2 and Th(NO3)4 as chemicals. I also have some thorium gas mantles and minerals too. I have a huge thorite specimen, and it's hot. I collect radioactive sources of all kinds, and I try to find the hottest sources I can find!
This is bad reasoning. UV causes the most because its the one we're exposed to the most. And not that many people get skin cancer considering almost everyone goes outside everyday
On cameras of the same age as the lens, there would always be a layer of steel (the camera back) between the lens and the photographers face. How about testing the exposure through thin sheet steel? Modern cameras are mostly plastic, so less protection there, but the lens is always about 3 inches away from the face, so maybe test how much the radiation falls off with distance? In fact, try lens, then three inches of air, then sheet steel. Also: the viewing system (mirrors and lenses) has no effect on radioactive emissions, (won't focus them) so your eye is not at any more risk than any other part of your face. Thanks for doing this.
I am quite happy with it, i built a cmos 555 driven frequency generator, that drives a voltage ladder to get to the 400v or what ever it was. then i used an microprocessor and lcd to get the count
Great video. 2 questions. Is it gamma spectrometry or spectroscopy? And do you know of any good websites or resources where I could learn more about nuclear physics( especially the math parts, I have a fairly good idea of concepts)? Anyways thanks for the frat videos and hope you have a nice day.
It really should be spectroscopy, but spectrometry is fine too. I am working on a math video, right now! I'm starting with decay equations (exponential decay and parent->daughter->stable bateman equations). I'll likely add some info on branching too. If you are interested in gamma spectroscopy, I'd recommend Dr. Gilmore's book on the subject. www.amazon.com/Practical-Gamma-ray-Spectroscopy-Gordon-Gilmore/dp/0470861967 I'd also recommend getting a Ti-89 Titanium. I can do basically any math on mine and as calculators go, I personally think it is second to none :)
The lead in the front element's glass may be shielding the thorium emissions from the rear element, hence the varying activity levels front to back. Different glass compositions were used depending on the properties required for best optics.
+Blacklight8001 Radiation from a banana is higher! K40 has a half-life of 1.25x10^9 years; Thorium262 1.4x10^10 years; Meaning there is ~1/10 the amount of radiation being emitted from the lens vs a banana...
Microwaves release non-ionising electromagnecit radiation which is not really dangerous and doesn't affect us the same way, this is ionising nuclear radiation which is very dangerous beacause it mutates and kills our cells.
So if I may ask, how have you not developed long term radiation sickness from this? For instance, if this is in microSievert readings, ~25 thousand is equal to that of about ~.00025th of a Sievert. Over long exposure times that has to crate some sort of problems...?
Radiation sickness comes from large doses and not from small accumulations. This lens puts out was less than 100 uSv/hr(perhaps 10-20 uSv/hr). This is only in my hand. By the time we measure it at my body, it is nearly down to background. The hands are the most immune part of the body. But... just for fun, let's pretend that the lens was massively more radioactive than it is and that my body received a dose of 100 uSv/hr (that would likely take dozens of nor hundreds of these lenses). At 100 uSv/hr, the dose rate would be about 10,000 times below the minimum dose rate needed for radiation sickness. Now, I am exposed to my samples for a few seconds to perhaps 5 minutes during a full year. So, my total dose from my samples is probably less than a few dozen uSv/year, max. Does that make sense?
Well yes, I truly believe that you are well qualified to be doing the studies over such objects that you are doing. I mean, other than the fact that you kind of have to be... But I digress. You seem fully trained to be doing such things that you are. But I may ask, have you done tests on common crystals (ie. Quartz or smoked quarts) that use small amounts of radioactivity to change the structures like in the smoked quartz that gives it the color that it has? Just an idea over it.
It looks like your lens is from the 1973-1975 time period. It looks like an SMC Takumar, which would be the last of the M42 thread mount lenses before Pentax adopted a bayonet mount. The earlier M42 50/1.4's were the Super Takumar (1964-1971?) and then the Super-Multicoated Takumar (S-M-C Takumar) from about 1971-1972 This is the version shown in my video.
antiprotons I bet if you specifically went for yellowed lenses you'd have good luck. Though some people will bleach thorium lenses in the sun to return them to full transparency.
Mark Rose Best bet to get a radioactive lens is to look at the list of radioactive lenses at Camerapedia. Some radioactive lenses are not visibly yellow -- an example is the Olympus 50/1.4, which I've had for decades (with no bleaching). However, this Takumar lens is one of the best, as far as radioactivity goes. It's very common and easy to find, and the radioactivity is well above average for 35mm format lenses.
Love your vids, I learn more about radiation being in every day items more and more. Your channel is wonderful, never stop making vids. You are a great host with great content, easy to listen to, and your enthusiasm comes across which is lacking in so many other peoples videos. Bravo Sir (Encore) ;-)
I accidentally had one of these lenses stored under my bed for 2 years attached to an old camera my father in law gave me. I've removed it now of course and bought a GMC 320+ Geiger counter to check out the beta and gamma coming out the thing. I'm getting over 1000 pcm at the back of the lens, but thankfully only 34pcm average when the lens is on the camera and in the camera bag, and 25pcm where I was laying in bed with the camera bag underneath. background levels average about 17pcm. Bit of a relief considering it was only a foot away from my balls for 7 hours a night for two years lol
I bought the same Geiger Counter. I have 3 vintage Takumar lenses that are radioactive. None read as high as this guy's lens.
Three of my Takumar lenses are radioactive.
One is 1550 CPM and the other 760 CPM. All on the back lens.
My Super Takumar read 2250 CPM on the back lens.
The rest of my vintage Takumar and FUJINON lenses have no CPM activity.
I bought these because they were radioactive. They are classic vintage lenses.
The CPMs really drop off fast as you move away from the lens.
At 2 inches with the cap off the back lens, the reading in around 165 CPM.
With the lens caps on and in an Olympus camera case I get about 100 CPM.
I have mine in my bedroom. It is really bad for health?
You know you are photographer when you was "oh, cool, f/1.4" instead "oh, cool, radioactive".
Yep, I am indeed a photographer.
I'm a noob when it comes to photography...but would the extra radiation "add" anything to high ISO long exposures?? ie with night/astro photography ?
Nope, has nothing to do. Probably only add more noise to the picture. ISO is just how sensible is the sensor to the light that gets in, when there's no other alternative to opening the aperture (the hole) wider to let more light in, or let the sensor get more light (longer exposure), higher ISO at the cost of noise and weird purple/blueish spots.
Kodak had some problems when the US began testing atomic weapons. Stored and unexposed film was getting ruined with mysterious spots. There is a cool documentary about it.
I actually was like "oh cool, f/1.4 and its radioactive!"
A long time ago (35+ years) I was an industrial chemist. The company I worked for made, among other things, various radioactive compounds (with a license from the NRC). One of the things I made on a continuous basis was Thorium Flouride. It was used by the camera optics industry, but not as an ingredient IN the glass (as in your exampke), but as an anti-reflective coating ON the lens. It was vapor deposited on the lens surface in a layer that was only a few molecules thick. I was told at the time that with a layer that thin, the amount of radiation from the (tiny) quantity of Thorium present on a single lens was nearly impossible to detect. (Of course, since I was making kilograms of the stuff at a time we had lots of radiation monitoring going on!)
i don't get it,is the coating prevent us from the radiation OR just a trick?That was terrible that people did do that to the humanity.
Asahi = "Ah-sah-hee"
Thoriated glass has great optical properties but it is a little radioactive. After many years Thoriated glass gets a yellow tint due to the radio decay.
Many of these lenses with thorium oxide elements have insanely good optical qualities, especially for when they were made. Elements with thorium oxide(up to 30% by weight) have high refractivity and low dispersion, which helps reduce chromatic abberations as well as facilitating the use of less curved elements which are easier to manufacture. Very similar technology is still being used today. Canon's very high end L-series lenses, especially the telephoto ones with white barrels, use fluorite elements. Fluorite elements have a crystaline structure that is almost identical to that of thorium oxide, thus giving fluorite glass the same properties as thorium oxide glass. The use of thoriated elements has pretty much entirely stopped with the advent of the newer types of ED glass, many of which compensate for abberations better than fluorite or thoriated glass. I personally own a Super Takumar 50mm 1.4 in m42 screwmount from 1962 that uses thoriated elements, and it is easily the best lens I own in terms of image quality. It honestly does a better job than many of my much more modern lenses, both on film and on digital.
What is ED then?
VicariousReality7 ED just means extra low dispersion glass. There are many types of ED/ Low dispersion glass, including Fluorophosphate glass. Most modern types of low dispersion glass are just trying to get the benefits(and physical/optical properties) of thoriated or fluorite glass without any of the disadvantages, like fluorite's weakness and heat sensitivity or thorium oxide's radioactivity. In the end they accomplish pretty much the same thing, the reduction(or outright removal, in the case of superachromat lenses) of optical abberations.
I have a Takumar 50 1.4 and yes , I always find myself going back to this lens for the sheer beautiful pictures that it produces.
At these levels (of radioactivity), it could be bad for health? No, no? Im very ignorant 🙃
Some day we will all die😂 I would much rather be killed by my lenses than GMO stuff and other supermarket “food”🤪
I would be very interested in knowing the health implication of these specific numbers you are pointing...thanks
None. You get more damage by passive smoking and car fumes you breath daily... or by the chemical in your breakfast food and sausages you eat.
As Michele said, not very. The actual gamma dose rate to your head while using a lense like this is very low, especially when compared to cruising at 35,000ft. The LND7317 geiger tube in the Inspector USB is a very sensitive tube, especially to the large number of beta particles coming from the lense, which geiger tubes - especially ones with thin mica windows like the LND7317 - are excellent at picking up, so the lense sounds very active indeed! But what you have to remember is that these practices are mostly blocked by the body of camera and have very low penetrative power.
You would receive a dose my orders of magnitude higher than this from a simple X-ray.
That being said, if you're stupid enough to stick this thing to your eye ball then, yes, it can have a detrimental effect to your beta sensitive eye lense...given enough time.
@@longden57 you can't just say that,every opportunity that increases health problem need to be concerned.
@@lanchanoinguyen2914 The science and statistics would suggest that you need to be far more concerned about the air you breath walking around a city than you should be about the very small amount of time spent holding this lense! Everything is relative...
I'm exposed to doses FAR in excess of this for my own professional nuclear research work, and yet the doses I'm allowed to be exposed to on a daily basis (full body doses no less) are still insignificant when compared to just a few minutes spent at hospital in a C/T scanner. You really need to run the numbers...if you're concerned about the risk from this lense, then you are woefully ill-informed of the day-to-day risks associated with life as we know it, and to the physics of the interactions between matter and radiation.
Please do your research.
Thank you.
This surprised me that at the time when the lens were being used there wasn't a huge health advisory sent out. It could be extremely dangerous if the lens were broken or even worse shattered.
I don't think just broken would be much of a problem, shattered maybe. Glass isn't very friable
I'm not sure if its been mentioned, that lens was manufactured from 1972 to 1975.
older lenses like Leica, particularly from the late fifties and sixties came with a radioactive brush to wipe a cross the lens to get the dust off of it.
I legit just moved all my vintage camera stuff away from my bed which where they were
Plastic blocks most alpha partials from these lenses. Plexiglass in fact. I just bought a Olympus OM-System G.Zuiko Auto-S 55mm f1.2 1974 Radioactive 3389 CPM lens. It is hot. More on the front lens than the back. Back is 950 CPM. The front is 3389 CPM. After reading this paper on the use of plastic to block the Alpha partials I stacked four 0.25 blocks of plexi on the front of the lens. Using GQ GMC 320 Plus I was able to measure a drop from 3389 CPM to 540 CPM. Just think about what 2 inches of plastic would do. Now that is news.
I have a GMC 320+ Geiger Counter.
I have 3 vintage Takumar lenses that are radioactive. None read as high as this guy's lens/counter.
Three of my Takumar lenses are radioactive.
One is 1550 CPM and the other 760 CPM. All on the back lens.
My Super Takumar read 2250 CPM on the back lens.
The rest of my vintage Takumar and FUJINON lenses have no CPM activity.
I bought these because they were radioactive. They are classic vintage lenses.
The CPMs really drop off fast as you move away from the lens.
At 2 inches with the cap off the back lens, the reading in around 165 CPM.
With the lens caps on and in an Olympus camera case I get about 100 CPM.
Wouldn't the beta particle hit the camera sensor and create white noise?
Thorium compounds, and isotopes. Fun stuff! Asahi was originally a rubber company, and made the rubberized silk shutters for the old K1000 series Pentax cameras. Now Ashi is supposedly an optics coatings company. We also use thoriated tungsten in transmitting vacuum tubes. Lots of camera lenses have heavy thorium in the glass. The rubberized silk shutters are really incredibly robust, especially compared to the ME era metal fan type shutters. Those tended to warp, and they won't fully set or reset. The rubberized silk just does it's thing, and it does it very well. I loved the ME Super, and Super Program Pentax. Small, smart, semi automatic, and just loads of fun.
These lens are supposed to have a yellow hue. These lenses with
thoriated glass provide excellent contrast and tone. Made in the 1970's the lenses like this with doped thorium glass were expensive and VERY good. I think these lenses are only really dangerous if you swallowed it!
It's interesting how unlike our eyes, digital cameras CAN indeed detect gamma rays (as well as x-rays) at very high intensities though I don't know why they appear as dots rather than light as they should but I'm guessing the dotted effect is due to the fact that most of the photons just go straight through the camera's CCD.
I wonder would putting those lens up to a digital camera give you that cool effect; I've seen someone get that effect just by placing pitchblende ore up to a digital camera.
Hmmm... This lens is for film SLR camera. I wonder how much it causes fogging of the film due to radioactivity? Especially for long time not moving film to the next position and/or for long exposure.
I wondered the same thing!
Got one of these on order. So not only will it be great for photography, but also a nice test source for my Geiger counters. I may or may not do the UV treatment thing. I will take some shots and then decide.
Have you thought about encasing the lead in a polymer? Maybe a two part resin? That might last longer than the paint.
+dnelms2 I have not, but I might. You are quite correct, a paint does not last that long.
So, my three vintage Pentax cameras have some Thorium on the lenses? Interesting.
Thanks for this review. What reading would a banana give compared to the tak?
What would the radioactivity do to photographic film in the camera? If it was a problem, every picture would be ruined !
Beer, wine and all alcoholic beverages for sale in the US by federal law are required to be radioactive.
Any idea why?
Because the radioactive carbon-14 proves its made from plant matter and not oil...
aj ledezma You got it. May I ask how you know?
The alcoholic beverage industry in the US got a law passed requiring alcoholic beverages form human consumption to be radioactive. (Oil companies could make high quality alcohol very inexpensively from oil.)
If alcohol is radioactive it means it came from something which was recently living.
I was told just a few years ago the US seized a containers of wine from Italy because the wine was not radioactive. (It was made from oil.)
Passed High School Physics WTF I think this is a result of that stupid Mith about everything being ion-radiating, when only some elements and isotopes are.
My dad: don't drink that chemicals it is radioactive
Me: it is carbonated water
My dad: then why does it say carbonic acid.
Me: because it is its chemical name
My dad: *confiscates H2CO3*
Me: ok I'll just drink hydrogen Oxide.
My dad: no that's poisonous.
Me: it's water. Ok I'll just have some sour salt for snack.
My dad: it says citric acid it must be radioactive.
Me: ok I'll just drink a sodium hypochlorite solution because you won't let me drink water.
My dad: ok I'll have double
You know what happened next
Would alcohol be dangerous if made from oil ?
This is so cool! Thanks for making your videos.
When switching to the front lens the count is lessened because the distance to the source has increased several times; not so much that the front element is blocking the radiation. In the examples of radioactive camera lens I've seen, the radiation always comes from the rear element only. I've taken elements out of the housings and also found that the radiating piece of glass is more intense on one side than the other. That suggests that it is the coating rather than the entire glass that contains Thorium --- the radioactive isotope. This is contrary to the literature I've seen which claims that the entire glass is doped up to a third of its weight.
Actually I do not think the lens will be "pointing directly at your eyeball" when you open the shutter to take an exposure. You will still have the pressure plate, usually metal, and the back of the camera body. I don't know though what effect this would have on blocking the different radiations. What about distance? How much would your reading decrease if you moved back 1 inch, 2 inches , etc.?
The change in reading with respect to distance is governed by Distance Inverse Square.
Intensity at point B from point A:
B = A/(4πr^2) where r=distance.
So, for a unit squared, perhaps 1 inch squared, the change in intensity is:
Inches Intensity
0 1
1 0.0796
2 0.0199
3 0.0088
4 0.0050
10 0.000796
100 7.9578×10^-6
Distance inverse square.
Haha! You're still at it. Glad you're still pumping out videos. Keep up the good work sir.
Can anyone help me out with this? I have the Nikon NIKKOR-Q 135mm f2.8 NON-Ai lens & I am wanting to know if this lens is Radioactive in any way? Any help would be greatly appreciated!
put the lens to the sun to remive the yellowing.
i checked mine, 0,5 mR/h x100 that means 50mR/hr.
Used on the camera, probe on the back of a pentax spotmatic i read 0,2mR/hour at x1 so no big deal to use it.
I bought Mamiya/Sekor from Tomioka, and it's radioctive too.
I wouldn't worry about the radiation from these camera lenses. It sounds scary on a Geiger-Müller counter close-up, but in reality, it's not much. And the glass attenuates some of the radiation, too. Thorium-232 has a half-life of over 14 billion years, making it weakly radioactive. Its decay progeny has shorter-lived radionuclides, thus more they're more radioactive, but it's still not much. And they are nice lenses.
What cpm is the same as an xray
wouldn't the radioactive camera lens result in exposure to the photographic film?
+Spock Some, yes. (I had the same thought). The reasons it makes little effect are:
1. Higher energy photons from ionizing radiation have a high chance of simply passing through the film and not depositing energy in it.
2. The actual intensity is low (photons/s). Millions of times less than light.
3. The film is more sensitive to the visible spectrum, most of the time.
But given a really long time I suppose it would.
+antiprotons isn't cause of cancer only related to statistics in this situation? could single radiation source of this kind of takumar lens cause cancer cells? hwo about immune system? i love MF lenses but i choose not to keep takumars. they are very good at micro contrast and have very low CA., but no thanks.
+antiprotons i've heard if you put a radioactive lens on undeveloped polaroid film it will leave a glow.. have you found that to be true?
Photographic Elements
Have not tried, but it seems reasonable to believe. Might take a while to expose.
maybe if you left a roll of unexposed film wound in the camera over 10 years with the lens on.... in a freezer to prevent emulsion damage from time/heat.
In day to day usage, will the lens harm me? I use it for portraits. It's not like I cuddle with the lens every night but I do always carry it with me. What will the radiation actually do to my body that my cell phone in my pocket isn't already doing ?!
I haven't read all the comments,but wouldn't the radiation from the rear lens saturate the film to total exposure?
how about thoriated tungsten for tig welding machines?
Well, damnnnn. Wondering if photographers that used old school lenses have more incidences of cateracts.
Perhaps they have. I don't know of any good research done in that field. Having the lens close to your eyes for hours at a time or handling broken lenses are likely the only two ways to be affected by one of these (though, technically any dose of radiation increases your risk of cancer).
I used to be a photographer, but none of my lenses were hot. :)
Since the cameras used are/were largely if not completely metal I would guess that gives at least some protection. The back of the camera is certainly metal. The shutters in Pentaxes these lenses were used on I think were fabric although some other SLR shutters were metal. When the photographer is using the camera he is looking through the lens via two optical reflections, the mirror behind the lens and the pentaprism. I don't know if the mirror has metal on the back of it or not. Perhaps the greater reading from the back may be due to the rear element being the culprit? I would guess the lens has from 5 to 7 different glass elements, possibly of different glass formulations. If the radiation is coming from the rear glass would some of the intervening glass when measured from the front or the short increased distance decrease the reading?
***** There are two things in play: The beta and alpha from the glass, which are blocked by the casing at glass easily, and the gamma/x-rays from the glass. The gamma and x-rays will pass through the lens as though it were not there. The metal will only shave a few % off of the gammas.
My scintillator gets a nearly uniform reading, but my alpha/beta/gamma sensitive Geiger counter has vastly different readings due to the glass.
antiprotons You were getting vastly different readings between the back and the front with both devices, weren't you? Doesn't that imply the culprit is the rear element? Is the lower reading from the front due to distance? Does the radiation follow the inverse square law and IF the radiation was coming from the rear element it would be greatly less even a slight distance away?
***** You have several things in play:
Change in intensity with respect to distance.
Change in intensity with respect to attenuation.
Change in intensity from intervening objects.
All of these reduce the reading. I suspect the back is the culprit.
so broken camera lens dust if inhaled will be very dangerous?
It could be. I wouldn't recommend it.
antiprotons yea it will bring more than 7 years bad luck!!
probably increase lung cancer risk
What you can tell about lenses with lanthanum? Can it be radioactive?
The brown discoloration often seen on this type of lenses is easily removed with a small and inexpensive LED desk light from Ikea. Place the lens without the caps on a mirror. Position the LED head about an inch above it.
Let it shine, let it shine, Let it shine.
Occasionally turn over the lens for even exposure. Takes a day or 2.
NEVER leave a lens in the sun. The lubrication will melt and you end up with sticky aperture blades.
Although i don´t believe this radiation can cause severe damage i am pretty much surprised! I wonder if i need a lead protected case for my own lens collection...
Wouldn't that much radiation interfere with the CMOS sensor, creating white snow and noise?
Wow, we have the same question out here.
If you like your radioactive camera lens, you can keep your radioactive camera lens.
umm... Okay. I guess I'll just keep my lens; that was already mine and that I was already keeping. lol
Quick question, how protective do you think Mercury is against radiation? I know its denser than lead so....
Would you mind checking for us if any of the telescope eyepieces out there are rad?
In fact staying up late to remove the yellow cast from the radioactive element probably kills my health more... I have two Pentax lenses that are radioactive, and they take excellent pictures, except removing the yellow cast is pretty hard.
it's really bad for health?
I'm wondering about the workers who built these lenses. How much exposure did they receive I wonder?
No idea, but I would suspect that they were exposed to quite a lot. The workers who made all of this radioactive stuff are often ignored. Here is a neat video showing how thorium was extracted and processed in India. It's creepy to watch the workers handling all of it: Atomic Fuel India
antiprotons My grand parent's old off-the-grid place used propane lanterns for lighting with... thorium mantles. No doubt everyone there, myself included, inhaled/ingested bits of thorium oxide dust :D
Even to this day, thorium is still used in mantels.
antiprotons It's tough to find them though! All the ones I've found for sale around here are thorium-free (using yttrium instead, I suspect).
I'm not sure if you've done any research on this, but many people have found that exposing the rear element to various types of light sources seems to reverse the yellowing process. Any idea what process is happening to cause that?
different lens elements can be made of radioactive glass due to its optical properties (chromatic dispersion, refractive index)
that is why backi of lens radiates
Hallo! Thanks for the video.
I have got an SMC Pentax 50 1.4 (not the Takumar) for years and its lenses don't seem yellowish but on the other hand I'd like to know if they are all radioactive or if is there at least a kind of serial index to determine if an SMC-M Pentax 50mm f1.4 is or not radioactive.
Does anyone know anything about? Thank you
thank you so much for this video and for all the insightful comments below. it has really helped put the photography community at ease. i'm still curious about one thing.. if the rumor is true that leaving a thorium lens in sunlight for three days makes the yellow go away, how does the uv react to thorium in such a way and how long before the yellow returns? thank you again.
+Photographic Elements Unsure, but I have heard this too. Might be some sort of heat treatment
It would be more helpful to also give measurements on the μSv/h scale.
Do gamma rays bounce through lenses the way visible light does? Well, not exactly the same, they'd suffer a lot of chromatic aberration. What about other ionizing radiation?
Higher energy photons, like gammas, tend to go right through most matter. Lower energy photons, like light, sort of "splash" off of material, bouncing here and there.
To a gamma, the camera lens is nearly transparent. This is the same for x-rays and beta's. Alpha's cannot penetrate more than a few micro meters of the metal.
Do you know of any material that acts as a lens to gamma radiation? I should probably read up on how light interacts with solids.
nealshireman I do not. It mostly scatters (compton scattering). It could be possible, but I doubt it would be easy.
I would like to know if he would be testing different cell phones. They have a large screen and some optics employed...
I just tested Rokkor PF 1.4 with GMC 300E+ bought on Amazon, and the background radiation is about 0.1 MicroSv/hour. The GM counts about 18 average through apartment. At Rokkor PF it doesn't change but this is GM of a 100$ and it doesn't count alpha. What is your opinion, about measurements. Do I have to go further buying Alpha detector or this is enough to conclude measurements and happily use Rokkor 1.4. Thank you very much.
stickom I would not personally be that worried about the radiation from a single lens. The alpha counts make them seem pretty hot, but in the scheme of things they are actually pretty low level. Beta and gamma from a thorium lens are not particularly intense most of the time, which is why your Geiger counter isn't picking them up.
What is the dose rate? The count rate is very equipment dependent.
I don't really understand all of this, buhut can anyone tell me how many microsieverts that is, for comparison.
Two things I would like to have seen:
1. Do your geiger counter reading through one layer of aluminum foil. That's just for curiosity. and
2. Do your reading through a thin sheet of steel to simulate the back of a typical (Pentax) camera. The back of the lens is hotter than the front, but in actual use you would rarely be directly exposed to it. And, out of my field here, but I don't think the viewing system of the camera will refract/focus radioactive particles, so your eye is pretty safe, even at the instant of exposure.
In fact, it would be interesting to do the whole Geiger counter part of the test on a lens mounted on a camera, as it would be in use. Measure with the camera at rest (shutter closed) and fire the shutter on "Bulb" or "Time" and see if any more radiation comes through.
I just looked up the half life of Thorium 232. It is 14050000000 years, and it emits alpha particles as it decays. I don't think that you would measure a lot of counts from glass containing a small percentage of that isotope. Are you sure about your spectroscopy?
You can get rid of the yellow tint if you leave the lens in a direct sunlight for several hours. But it won't get rid of the radioactivity :)
Just bought a Pentax Spotmatic with one of these lenses on it. Great presentation. The current mythology on these lenses is that if you expose the lens to direcvt sunlight for a few hours/weeks/months (depending on which blog you read) the yellow will disappear. But if the radiation is bcausing the yellowing, and presuambly the lens will be radioactive far after we are all gone, that seems unlikely, don'
don"t you think?
Was that thing called a Geiger meter or something?
Hey, great videos. I read some of your explanations below. I'm curious at what point would the radiation levels coming off a sample would cause you concern? In uSv/hr.
Well, concern relates to risk and concern over risk... so this is more of a question of when I would be worried.
If my sample had a dose rate of more than perhaps 1 uSv/hr at 1 meter (above background), I would not want to keep it. That is still very low, but beyond what I would be comfortable owning.
I could not want to approach anything above around 100 uSv/hr at one meter, for more than a few minutes.
Perfect. Just the answer I was looking for. Thanks.
I have the Konica 57mm F1.2 which is also radioactive. It's a fantastic lens but does have the yellowing as well. Simply add some blue in photoshop to counteract the yellow and you're fine.
Also, I don't worry about the radiation at all because you'll get much more radiation flying in a plane than you'd ever get from using a camera lens. People hear an item is radioactive and immediately fear it without knowing that you're bombarded by radiation every day just waking outside.
And your device you using to wach this vid k have a lot of stuff in me room so I am have radiciec stuff in me room
+mavfan1 The Thorium leaves a yellow-brownish cast on the glass after a few years. You can rid the glass of that coloration by exposing the lens to U/V light for 30-40 hours. I've heard of success just leaving the lens outdoors for a few days. The lens clears up all by itself.
+TheCondoInRedondo thanks for the tip. I'll give it a try.
short burst of big amounts of radioactivty is more dangerous than over a long time
+Speedyjens of course, but you don't get big amounts from using the lens, it's small amounts over a short time vs. small amounts over a long time in a plane, which is worse.
Asahi is a huge glass company in Japan. They also have the monopoly on thin, optical grade LCD panel glass.
I wonder how much cpm with the inspector usb with a 1minute timed count at contact :)
so we good to go on buying a canon aspherical lens? they radioactive too?
Do you know what the dose would be in millisievert?
what about film fogging from the radiation?
Hello, I wanted to ask you how you are with the spectrometer "Gamma Spectacular" Gs 1000 ... !!
And 'good .....! ??
You've heard of the Theremino .... !!! ????
Hello
Mirco
I am not sure but I completely understand your question. I really like the gamma spectacular but I use it with PRA 8. I did not really have much success with Thermino. Normally, I use my UCS 30 from spectrum techniques, but I find that the gamma spectacular is very useful in the field. It small and portable and works from my laptop without any trouble. The UCS 30 requires higher voltage and is more of a laboratory equipment.
Imagine wearing that camera around you neck for a few vacations or a job... sheeesh ... lol
Used to be a photographer who doesn't know how to pronounce ASAHI...
+Chihaya Komatsu
What is that even supposed to mean? Asahi is a single company, not the art. I shot canon (as well as a Wardflex TLR 120mm and Ricoh). Back in the early 90's we didn't have access to the web like we do today so it was possible to not know about something in utter detail.
+antiprotons hey, isn't the radioactive level unsafe?
MYSTERY READER (the original) Not really. It seems high because my detectors are sensitive. lol
antiprotons well...I hope you live to old age anyway, I dont know anything about radiation just that it's bad. And that it doesn't give you powers XD
Zoë Lkjsdhf bet he also pronouce Nikon as “nay-kon”
Here are just the isotopes of Cobalt (including Cobalt 60). 27 Co Cobalt 47Co, 48Co, 49Co, 50Co, 51Co, 52Co, 53Co, 54Co, 55Co, 56Co, 57Co, 58Co, 59Co, 60Co , 61Co, 62Co, 63Co, 64Co, 65Co, 66Co, 67Co, 68Co, 69Co, 70Co, 71Co, 72Co, 73Co, 74Co, 75Co
Yeaaaaaaaaaaaaaaaaah don't think this is going on my Christmas list! :)
Where do you find/buy the radioactive samples from? I know it is something labs, but I forgot. Thanks!
is it dangers? and is it only appears on old lens?
Junpeng Chen no, only if you eat it, check the box.
I got a question whats you opinion on LFTR reactors?
They seem like a good idea, to me. I believe we need to get Fusion working. Lockheed Martin's Skunk Works says they will have a working prototype for commercial use in 5 years. We shall see. www.lockheedmartin.com/us/products/compact-fusion.html
The LFTR design is much better looking than our current BWR and PWR's. They are likely safer, easier to maintain, and can be used to get rid of some nasty existing materials. The idea of having a coolant/fuel mixture is also impressive.
I do worry that countries may use such devices to created weaponized Np237 devices, but what can you do?
Very nice! And it's relatively safe too! It's one of the few commercial products that is radioactive that I don't own . . . yet. But, I do have ThO2 and Th(NO3)4 as chemicals. I also have some thorium gas mantles and minerals too. I have a huge thorite specimen, and it's hot. I collect radioactive sources of all kinds, and I try to find the hottest sources I can find!
I understand if you don't want to of course.
I just bought the super takumar 50mm f1.4 so am I safe to use it ?
OK so the question is, is it dangerous?
You realize UV rays tend to cause most genetic damage right? Better not go outside.
This is bad reasoning. UV causes the most because its the one we're exposed to the most. And not that many people get skin cancer considering almost everyone goes outside everyday
On cameras of the same age as the lens, there would always be a layer of steel
(the camera back) between the lens and the photographers face.
How about testing the exposure through thin sheet steel?
Modern cameras are mostly plastic, so less protection there, but the lens is always
about 3 inches away from the face, so maybe test how much the radiation falls off with distance? In fact, try lens, then three inches of air, then sheet steel.
Also: the viewing system (mirrors and lenses) has no effect on radioactive emissions, (won't focus them) so your eye is not at any more risk than any other part of your face.
Thanks for doing this.
canon camera bodies are made from magnesium alloy too
What do you usually get for background? I get about 10-20cpm. But I am not sure how accurate my counter is as I built it myself
+membola It very much depends on the device. It sounds to me like you have a small tube, such as an LND712 or 713
Yes, I have a small tube, an SBM-20u.
membola Ah, a Russian tube. It still sounds like a neat detector.
I am quite happy with it, i built a cmos 555 driven frequency generator, that drives a voltage ladder to get to the 400v or what ever it was. then i used an microprocessor and lcd to get the count
Great video. 2 questions. Is it gamma spectrometry or spectroscopy? And do you know of any good websites or resources where I could learn more about nuclear physics( especially the math parts, I have a fairly good idea of concepts)? Anyways thanks for the frat videos and hope you have a nice day.
It really should be spectroscopy, but spectrometry is fine too. I am working on a math video, right now! I'm starting with decay equations (exponential decay and parent->daughter->stable bateman equations). I'll likely add some info on branching too.
If you are interested in gamma spectroscopy, I'd recommend Dr. Gilmore's book on the subject. www.amazon.com/Practical-Gamma-ray-Spectroscopy-Gordon-Gilmore/dp/0470861967
I'd also recommend getting a Ti-89 Titanium. I can do basically any math on mine and as calculators go, I personally think it is second to none :)
How do you dare to put the lens open in the carpet fill with dust!
The lead in the front element's glass may be shielding the thorium emissions from the rear element, hence the varying activity levels front to back. Different glass compositions were used depending on the properties required for best optics.
Could very long exposure cause cancer ect?
+Blacklight8001 Radiation from a banana is higher!
K40 has a half-life of 1.25x10^9 years; Thorium262 1.4x10^10 years; Meaning there is ~1/10 the amount of radiation being emitted from the lens vs a banana...
Oh, and I eat bananas all the time! :P
half-life does not translat into radiation amount.
+Creativity Overflow it kind of does actually, as the shorter the HL, the faster it decays and the more particles it gives out.
Why are certin areas more active than others?
The back of the lens is where the highest thorium content lenses are. The lens housing shields me from a little of it, making a very uneven emission.
antiprotons OK thanks
So why do the lenses use radioactive material? I'm guessing it is somehow beneficial to the quality of the lens or something?
+Dan Coulson Yes. It's not the radioactivity, it's the thorium (which happens to be radioactive) lol
Many thanks for your research!
Will you use ever this lens?
what for you need radioactive lens??
Is the radiation of the lens more dangerous than the microwave oven?
Microwaves release non-ionising electromagnecit radiation which is not really dangerous and doesn't affect us the same way, this is ionising nuclear radiation which is very dangerous beacause it mutates and kills our cells.
So if I may ask, how have you not developed long term radiation sickness from this? For instance, if this is in microSievert readings, ~25 thousand is equal to that of about ~.00025th of a Sievert. Over long exposure times that has to crate some sort of problems...?
Radiation sickness comes from large doses and not from small accumulations. This lens puts out was less than 100 uSv/hr(perhaps 10-20 uSv/hr). This is only in my hand. By the time we measure it at my body, it is nearly down to background. The hands are the most immune part of the body.
But... just for fun, let's pretend that the lens was massively more radioactive than it is and that my body received a dose of 100 uSv/hr (that would likely take dozens of nor hundreds of these lenses). At 100 uSv/hr, the dose rate would be about 10,000 times below the minimum dose rate needed for radiation sickness.
Now, I am exposed to my samples for a few seconds to perhaps 5 minutes during a full year.
So, my total dose from my samples is probably less than a few dozen uSv/year, max.
Does that make sense?
Yeah, I was just wondering because of your casual handling of radioactive objects. Thanks for the clarification!
Chris Miller It would not be casual if I were confronted with a truely potent source.
Well yes, I truly believe that you are well qualified to be doing the studies over such objects that you are doing. I mean, other than the fact that you kind of have to be... But I digress. You seem fully trained to be doing such things that you are. But I may ask, have you done tests on common crystals (ie. Quartz or smoked quarts) that use small amounts of radioactivity to change the structures like in the smoked quartz that gives it the color that it has? Just an idea over it.
Sorry if that first part didnt make since. I meant that as you would be fully prepared to take on higher radioactive potential materials.
We're did you learn all of this and how long did it take?
"ah SAH hee"
I did not know this lens was radioactive and I spent about 40 minutes cleaning the one I purchase should i be worried?
No
hello i love to DSLR, is it on every DSLR lense have Radioactive?
art Jard Most are not (none of the new ones). This only occurs on old lenses... and even then only a few.
thank you so much for the information..
It looks like your lens is from the 1973-1975 time period. It looks like an SMC Takumar, which would be the last of the M42 thread mount lenses before Pentax adopted a bayonet mount. The earlier M42 50/1.4's were the Super Takumar (1964-1971?) and then the Super-Multicoated Takumar (S-M-C Takumar) from about 1971-1972 This is the version shown in my video.
I am just glad I got a good one on my first try. There were many to choose from an probably lots of non radioactive lenses.
=)
antiprotons I bet if you specifically went for yellowed lenses you'd have good luck. Though some people will bleach thorium lenses in the sun to return them to full transparency.
Mark Rose Best bet to get a radioactive lens is to look at the list of radioactive lenses at Camerapedia. Some radioactive lenses are not visibly yellow -- an example is the Olympus 50/1.4, which I've had for decades (with no bleaching).
However, this Takumar lens is one of the best, as far as radioactivity goes. It's very common and easy to find, and the radioactivity is well above average for 35mm format lenses.
***** Thanks for the info! I haven't yet added a lens to my collection.
Love your vids, I learn more about radiation being in every day items more and more. Your channel is wonderful, never stop making vids. You are a great host with great content, easy to listen to, and your enthusiasm comes across which is lacking in so many other peoples videos. Bravo Sir (Encore) ;-)
Thanks! I am glad that you like them!