Beta will not penetrate those three layers of rock slate. Most Beta will be stopped by a layer of hi grade aluminum foil (3mm thick). Therefore, the layered rock slate is only allowing the lens element sourced Gamma to penetrate. The non-background Gamma is coming from one of the last decay daughters of the Th-232 decay chain. Specifically , Thallium 208. This is the last stop before its stable daughter isotope...Pb-208. There is also some additional background radiation coming from the shield itself, as the composition is slate (rock). Clearly, at such short reading ranges, it could be a combination of any likely emissions (Alpha, Beta, Gamma). You would likely get a more accurate read of Gamma using 3mm thick alu foil. The beta could be acertained by putting a sheet of paper (instead of foil) in between and seeing the average count difference to factor out the Beta from the Gamma. Paper is more than enough to stop the Alphas. I would do this all on a wooden or plastic table as opposed to a granite or other rock like surface...these rock materials always have background radiation. Sorry for being a stickler. Used to be a Chemistry and Radiological Controls Officer on a nuclear fast attack boat...albeit 20+ years ago. :)
I've seen a oentax camera with that lens for a bargain price, just wondered if that radiation is a risk or harmful? What precautions re storage and use of lens would I have to take? Just curious if it's worth the risk? 😊
I just checked the Takumar lenses that I have, and my 55mm f2 (s/n 8,000,737) gave off no radiation. Both of my Takumar 50mm f1.4's did though. The earlier one (s/n 6,385,716) showed a fairly staedy 15 micro sieverts/hour, and the newer one (s/n6,984,501) was half that at 7 micro sieverts. The meter I used is a Ludlum model 3 with current certification. All three lenses have roughly the same yellow tint to them, and I tested them with the probe basically touching the rear elements.
the yellow cast isn't thorium. It is the reaction of the adhesives to the thorium. There are some lenses that have thorium and do not have such a yellow cast since they changed the adhesives. You can bleach the yellow out with UV lamps or sunlight.
actually its neither one, its a shift in the glass color due to radiation, same reason old BALL jars turned purple due to UV. no no no no no no, its NOT the adhesives, you can see the yellow element BARE here, without adhesive fockert.xs4all.nl/~pentax/radioactive_lenses/radioactive.html
The Canadian balsam yellowing from the thorium is usually the cause. The guy doing this article you posted said he did not remove the balsam from the glass.
Hello! I have a super takumar 50mm 1.4 whose serial number is 1728898 but as it is a little yellowish I thought it had thorium. However you say that those below 1780000 have no thorium. Am I right? Thankss
Hii.I have a different question. I bought 3 vintage lenses. These lenses are made with radioactive material. There is dust on the 2 lenses and around the edges. Could this dust come from inside the lens? So, can thorium come out of the lens in powder form? Respects
Hi! I was looking into buying a the 55 1.8 Super Takumar to use it as a portrait lens on my XT1 being the fuji 56 a little bit too expensive for me at the moment... Do you know wich series is the best? The super multy coated version ? are those still radioactive? and what about the 50mm ? THX
Since Thorium emits alpha and gamma, but not beta, that is more likely just gamma you are getting, unless there are further decay products emitting beta.
Theoria Apophasis does this partial redoactivity apply to ALL Takumar Lenses? I just bought a Super Takumar 8 Element 50 1.4 Serial number 1393172 which I have not received yet but from photo looks a bit yellow, a SMC 85 1.8 5694751 and a 135 f/1.8 Serial Number 7577798?
I sold my only radioactive lens, the Konica AR 57mm f/1.2. It was a nice lens, but didn't get as much use. Always wondered how much it really gave off.
I just purchased one of these lenses and it won't work on my Canon 5d IV because the aperature lever blocks the mirror. Would it be dangerous to cut the tab and aperature lever down because of the radiation??? Thanks
@@KenTheoriaApophasis thank you for reply! I learned it knocked the zeiss planar off the top when this first came out- Maybe i souldnt use it on my $$$$ body, not worth the risk maybe?? Ive learned alot watching your lens reviews- stay safe/ be prepared - Cheers from Missouri
Hi, I bought a SMC Takumar 35mm f2 and it has some fungus and I was planning on open it and clean it with Hydrogen Peroxide, I wanted to know if it’s dangerous to do that. I hope you can help me with that, I have been looking online but I couldn’t find anything.
Hi Ken, what tipe of adaptor do you sugget to mount this takumar on my nikon D300S? I mean the type with additional lens for infinity focusing or the bare metal ring?
Thank you very much. Your video just dissuaded me from buying one of these lenses for $15! Now back to eBay to see if I can find me a $15 Geiger counter 😁
Could I ask, is this a nice lens? I have been given my father's lenses collection and this was in it. The serial number is 252929 so an early ish model.
Do you have the Pentax-M 50mm SMC f1.4? Some of them were doped with Thorium, I'm not sure if mine is, the serial is 2million. The lens has a purple hue on the front and rear elements and not yellow.
SOME? NO ALL OF THEM WERE……yes, i have 4 of those lenses. look again, at the serial number ohhhh you dont have the SMC takumar, thats why www.flickr.com/photos/134746128@N05/30229490326/in/dateposted/
So Ken you were saying that people claim that it only emits alpha radiation, well from what i read it turns out that Alpha and Gamma invariably come together as in the process of alpha decay the original nucleus(father) splits to release a new nucleus(daughter) with changed numbers of protons. In this process the new(daughter) nucleus is in an excited state, to get the ground state the nucleus has to decrease its energy. There are different way to decrease its energy, be it as gamma decay or electron capture but the possibility of electron capture is very low. So it will come to ground state from excited state by releasing a photon of energy(gamma ray) equal to difference of both energy levels. I read this on Quora.
Did they stop to using thorium at some point with these lenses? I have a SMC 55/1.8 in the upper 5M S/N range and it's by far not that yellow. Or is it just because it's not as old?
Yeah! ;) Thanks - will find a place to store it away from my Fujis... By the way, the 50mm Nikkor pancake you recommended is a blast. Had to order two to get a decent copy, but was worth it anyway.
I've just mounted this lens on my Fuji and it's fab! Also got a cambron 35mm it seems hard work but gives good results unsure about cambron it was sitting around the house..
cheers ken, that's just mad...what a huge difference to the glass , I've picked up loads of vintage glass in the second hand shops and noticed the yellow and though the lens must be naff...but kinda wondering how many good purchases I have missed now :(
I have the LowePro ProTactic 350 Backpack for my Pentax 6x7. My cousin owns a Geiger counter and it started screaming at the 105mm when I asked him to scan my backpack. 😆
Awesome experiment! Watching the video generated two ideas: what would happen if you had two detector heads stacked? Would the gamma rays trigger both of them, or just the first one? I'm guessing both because if slate doesn't stop it, why would that thing stop it? Also, can you pick up alpha particles on the other side of the slate? According to Earnest Rutherford, you should be able to. He says they will "quantum tunnel" through, which is just his way of saying he doesn't know how the alpha particles end up on the other side. So he just made up a verb for the process and went with it.
Lmao Osha recommends 2.5 mrems/hr for whole body, OSHA Limits: Whole body limit = 1.25 rem/qtr or 5 rem (50 mSv) per year (approx. 2.5 mrems/hr for all work hours). Hands and feet limit = 18.75 rem/qtr. Skin of whole body limit = 7.5 rem/qtr.
Let's recharge the camera with that reactor. ps. most of thorium only emit alpha which can't penetrate your skin, so you are basically safe. But as you said, the dust could be dangerous. And It decays to radon which emit gamma, so you'd better to ventilate it often than just lock it up in the lead cage. pps. thorium radiation still could damage your sensor because some isotope of thorium emit beta.
hello, thanks for your videos, I have a smc takumar 50mm f1.4 that the serial number is 6 million, but the glass looks clear, is it radioactive? thanks
I see that the SMC 50 f/1.4 is radioactive, but I may have the early version of Super Takumar with 8 elements, maybe that one is not. Anyway...I love it!
The 8-element 50mm f/1.4 is NOT radioactive, according to what I've read. The improved refractive qualities of thorium glass allowed Asahi to make a cheaper, 7-element design that was as good as the earlier, very-expensive-to-manufacture 8-element design. The 7-element f/1.4 has the red infrared focus mark on the depth-of-field scale to the left of '4', the 8-element lens has the red mark to the right of '4'. This is only true for the 50mm f/1.4 Super Takumar; I have no idea about any other lens models.
Well.... actually.... for the last few months they have been in one of the many little storage boxes crammed into bed room so they are no more than 6 feet from the bed ! ! ! Those little gammas possibly whizzing through my carcass as I write this.... plus not having funds for expensive new babies I carry one in camera pack at all times !
it only takes a single corrupted cell to kick start cancer. FACT QUOTE: The only naturally occurring isotope of thorium is 232Th and it is unstable and radioactive. ... In addition to the alpha or beta particles emitted as a result of the decay of a parent isotope, most of the daughter isotopes also emit gamma rays.
A useful and engaging group of videos on this topic, Thorium. Adorama has a vid, "4 Ways to Light a Face." Now, I'm counting 5. ;>) I'll try live view on an external monitor instead of putting my eye near the radioactive source; the inverse square law applies, so the intensity of gamma radiation away from the tripod must be diminished, substantially. Tip: The inverse square law is more accurate if you put your studio inside a vacuum. Geiger counter readings presumably can be taken for Nikkors with thorium (di)oxide, like, I hear, the 200mm f/4 and 22 other Nikkors I have, now that I think about it. Excuse me while I go buy a lead vault...
let clear this out, in this Video you said " the radioactive of takuma 55 f2 start at serial over 1 milion" but in other your video you show 2 secret len auto takuma 55 f2 + yashica 5cm f2. The auto takuma 55 f2 serial start at 2xx,xxx then you said they are radioactive too. So what is the true ?
so we have tow choises :P buy below that serial number for safety and decent pictures ish, or buy above that serial number risk it and get AWESOME radioactive Bokeh and awesome Bandiwth... mmm tough choice here :P haha
really? i had another takumar at 1,750,000 that wasnt radioactive, but that was a SMC maybe they changed it earlier on the super takumars to an earlier serial Hmmmmmm
Ohad Pearl see if it warms your crotch after 10 hours of exposure, KIDDING!!!! actually if you grow alfalfa sprounts under the lens, if radioactive theyll shoot up faster than lightning
Yay, Pentax finally gets its day in the sun! In fact, given the emissions, you might almost say the sun shines out of their rear elements, ha ha... I have this model of lens, and the bokeh can be gorgeous. I also have the S1a film camera it came with. Epic, battery-free shooting all day long (as long as the film lasts), ably aided by my selenium-cell Sekonic light meter. The height of mischievousness would be to sell them to greenie hipsters to adapt to their gazillion megapixel Sony cameras.
I can't remember if EPIC TITS is the top level or one below the cat's arse. You love the lenses, now use the cameras. Borrow a K-1 if you can, shoot it against the D810, and tell us what you think. :)
Several people who've commented here clearly have *much* more experience with geiger counters (and accurate terminology). They've called into question his testing methodology and the implication that these lenses are inherently unsafe. Yet, I see no response at all. I've seen and learned from enough of his photography videos to conclude that he is indeed *amazingly* knowledgable about lenses -- yet, as has been pointed out, isn't familiar enough with the operation of a Geiger counter to accurately interpret what the readout is indicating. It's the lack of dialog that concerns me.. it's irresponsible to leave videos up in which the methodology has been debunked. At the very least I'd like to hear/see an update that takes this into consideration.
" Typical radiation levels can approach 10 mR/hr (100 μSv/h) as measured at the lens element's surface, decreasing substantially with distance; at a distance of 3 ft. (.9 m.) the radiation level is difficult to detect over typical background levels. For reference, a typical chest x-ray consists of about about 10 mR, a round-trip cross country airline flight exposes a passenger to 5 mR, and a full set of dental x-rays exposes the patient to 10 mR to 40mR. A study carried out by the Physics department of Sweden's Royal Institute of Technology estimates that total exposure to a professional photographer using a typical thoriated lens would amount to only 0.2% yearly allowable exposure to the eye and 0.17% to the whole body under the conservative standards of the Swedish Radiation Protection Authority. " source : camerapedia.fandom.com/wiki/Radioactive_lenses
Beta will not penetrate those three layers of rock slate. Most Beta will be stopped by a layer of hi grade aluminum foil (3mm thick). Therefore, the layered rock slate is only allowing the lens element sourced Gamma to penetrate. The non-background Gamma is coming from one of the last decay daughters of the Th-232 decay chain. Specifically , Thallium 208. This is the last stop before its stable daughter isotope...Pb-208.
There is also some additional background radiation coming from the shield itself, as the composition is slate (rock). Clearly, at such short reading ranges, it could be a combination of any likely emissions (Alpha, Beta, Gamma).
You would likely get a more accurate read of Gamma using 3mm thick alu foil. The beta could be acertained by putting a sheet of paper (instead of foil) in between and seeing the average count difference to factor out the Beta from the Gamma. Paper is more than enough to stop the Alphas.
I would do this all on a wooden or plastic table as opposed to a granite or other rock like surface...these rock materials always have background radiation.
Sorry for being a stickler. Used to be a Chemistry and Radiological Controls Officer on a nuclear fast attack boat...albeit 20+ years ago. :)
That glass is responsible for my large polished forehead!!
LMAO LOL
underrated comment 😂
My 1.8/55mm Super Takumar with the serial number in the 2.2 million range gives off about 15 micro sv/h when measured with an SBM-20 on the rear lens
So jokes aside.. Is it safe for daily use? Or to stay put on your camera the whole time, or storaging it near to yourself?
I've seen a oentax camera with that lens for a bargain price, just wondered if that radiation is a risk or harmful?
What precautions re storage and use of lens would I have to take?
Just curious if it's worth the risk? 😊
I just checked the Takumar lenses that I have, and my 55mm f2 (s/n 8,000,737) gave off no radiation. Both of my Takumar 50mm f1.4's did though. The earlier one (s/n 6,385,716) showed a fairly staedy 15 micro sieverts/hour, and the newer one (s/n6,984,501) was half that at 7 micro sieverts. The meter I used is a Ludlum model 3 with current certification. All three lenses have roughly the same yellow tint to them, and I tested them with the probe basically touching the rear elements.
could you link the catalog which shows the 1 780 000 is the beginning on radiationings ?
just bought a smc takumar 55 f1.8 from Roberts. serial number in the 7 million range should be good to go. thanks for these videos
My smc takumar 55 is at the 6.1 million range, is there any info on why later serial numbers are safer? (It has zero yellowing for some reason)
the yellow cast isn't thorium. It is the reaction of the adhesives to the thorium. There are some lenses that have thorium and do not have such a yellow cast since they changed the adhesives. You can bleach the yellow out with UV lamps or sunlight.
actually its neither one, its a shift in the glass color due to radiation, same reason old BALL jars turned purple due to UV.
no no no no no no, its NOT the adhesives, you can see the yellow element BARE here, without adhesive
fockert.xs4all.nl/~pentax/radioactive_lenses/radioactive.html
The Canadian balsam yellowing from the thorium is usually the cause. The guy doing this article you posted said he did not remove the balsam from the glass.
Hello! I have a super takumar 50mm 1.4 whose serial number is 1728898 but as it is a little yellowish I thought it had thorium. However you say that those below 1780000 have no thorium. Am I right? Thankss
Is it an interesting lens (beside being radioactive)?
ohhhhh hell yes , its awesome
Hii.I have a different question. I bought 3 vintage lenses. These lenses are made with radioactive material. There is dust on the 2 lenses and around the edges. Could this dust come from inside the lens? So, can thorium come out of the lens in powder form? Respects
It is mixed into the glass so no.
The radioactive range starts from 1780000 until what number?
whats a good geiger ? any recommendations ?
Hi! I was looking into buying a the 55 1.8 Super Takumar to use it as a portrait lens on my XT1 being the fuji 56 a little bit too expensive for me at the moment... Do you know wich series is the best? The super multy coated version ? are those still radioactive? and what about the 50mm ? THX
Since Thorium emits alpha and gamma, but not beta, that is more likely just gamma you are getting, unless there are further decay products emitting beta.
Theoria Apophasis does this partial redoactivity apply to ALL Takumar Lenses? I just bought a Super Takumar 8 Element 50 1.4 Serial number 1393172 which I have not received yet but from photo looks a bit yellow, a SMC 85 1.8 5694751 and a 135 f/1.8 Serial Number 7577798?
I have just seen reading further down the radioactivity list. Thankfully none of the above are radioactive. I am very happy.
Which serial number cutoff for 50mm 1.4 indicates an 8 element, non-radioactive lens?
is the non radioactive version take pictures that are as good?
I have this one with serial nr: 741416. Is that a version without radioactive glass?
I sold my only radioactive lens, the Konica AR 57mm f/1.2. It was a nice lens, but didn't get as much use. Always wondered how much it really gave off.
I just purchased one of these lenses and it won't work on my Canon 5d IV because the aperature lever blocks the mirror. Would it be dangerous to cut the tab and aperature lever down because of the radiation??? Thanks
i just bought a Super 50 1.4 to adapt to my fuji 😂 do just have to take it of the camera after I use it.. I'm a bit paranoid now.
Yes, he said that its not good for your camera if you leave it on. The electronics probably don't appreciate being bombarded with particles
Does it affect being near modern sensors?
yuuuup
@@KenTheoriaApophasis thank you for reply! I learned it knocked the zeiss planar off the top when this first came out-
Maybe i souldnt use it on my $$$$ body, not worth the risk maybe??
Ive learned alot watching your lens reviews- stay safe/ be prepared - Cheers from Missouri
I've seen a lot of 8million serial numbers. Are they not radioactive too?
Please test SMC Takumar 200mm f3.5..I plan to get one but too scared of radiation lol :)
The 85mm f/2 Jupiter Sonnar copy used it heavily.
I just bought a super takumar 55mm f1.8. The SN is 1072777. From the pictures the lens seems to have a bit of yellowing. Is this one radioactive?
Yup
Hi, I bought a SMC Takumar 35mm f2 and it has some fungus and I was planning on open it and clean it with Hydrogen Peroxide, I wanted to know if it’s dangerous to do that. I hope you can help me with that, I have been looking online but I couldn’t find anything.
Do you have any flickr sample pics from these lenses?
i havent posted any yet, i will this week, theres already a flickr page for this lens with TONS of pics from it
Does the yellow coating affect lens performance
Hi Ken, what tipe of adaptor do you sugget to mount this takumar on my nikon D300S? I mean the type with additional lens for infinity focusing or the bare metal ring?
Thank you very much. Your video just dissuaded me from buying one of these lenses for $15! Now back to eBay to see if I can find me a $15 Geiger counter 😁
how useful is this lens on. a Nikon body?
Could I ask, is this a nice lens? I have been given my father's lenses collection and this was in it. The serial number is 252929 so an early ish model.
Do you have the Pentax-M 50mm SMC f1.4? Some of them were doped with Thorium, I'm not sure if mine is, the serial is 2million. The lens has a purple hue on the front and rear elements and not yellow.
SOME? NO ALL OF THEM WERE……yes, i have 4 of those lenses.
look again, at the serial number
ohhhh you dont have the SMC takumar, thats why
www.flickr.com/photos/134746128@N05/30229490326/in/dateposted/
Based on the chart, it appears that I do have a thorium doped lens. The serial is at least 500k above 1.5M
@@wowgabewow So Planar Killer IS NOT RADIOACTIVE
What would it do to film left in the camera after a year or two ???
I have the same but f1.8 is it hot also
So Ken you were saying that people claim that it only emits alpha radiation, well from what i read it turns out that Alpha and Gamma invariably come together as in the process of alpha decay the original nucleus(father) splits to release a new nucleus(daughter) with changed numbers of protons. In this process the new(daughter) nucleus is in an excited state, to get the ground state the nucleus has to decrease its energy. There are different way to decrease its energy, be it as gamma decay or electron capture but the possibility of electron capture is very low. So it will come to ground state from excited state by releasing a photon of energy(gamma ray) equal to difference of both energy levels. I read this on Quora.
Is the 80's version of the 55mm f4 radioactive? Any help would be greatly appreciated
The latest SMC Pentax lens is not radioactive. The two older one's are.
Did they stop to using thorium at some point with these lenses? I have a SMC 55/1.8 in the upper 5M S/N range and it's by far not that yellow. Or is it just because it's not as old?
UR lens is radioactive :)
www.flickr.com/photos/134746128@N05/30229490326/in/dateposted/
Yeah! ;) Thanks - will find a place to store it away from my Fujis... By the way, the 50mm Nikkor pancake you recommended is a blast. Had to order two to get a decent copy, but was worth it anyway.
@@KenTheoriaApophasis How come they have n't used thorium on the 85mm and 135mm. What was the idea behind it. Interesting.
I've just mounted this lens on my Fuji and it's fab! Also got a cambron 35mm it seems hard work but gives good results unsure about cambron it was sitting around the house..
ahahahahhahaha!!!!!!!
dont leave it on there all the time, its radioactive :)
This lens danger for human healty ?
Ken can you show the difference between one that has been in the sun and another that has been stored in the dark?
see here
fockert.xs4all.nl/~pentax/radioactive_lenses/radioactive.html
cheers ken, that's just mad...what a huge difference to the glass , I've picked up loads of vintage glass in the second hand shops and noticed the yellow and though the lens must be naff...but kinda wondering how many good purchases I have missed now :(
Still, I've seen fungus growing on such lenses
fungus love radio active places
I have the LowePro ProTactic 350 Backpack for my Pentax 6x7. My cousin owns a Geiger counter and it started screaming at the 105mm when I asked him to scan my backpack. 😆
Awesome experiment! Watching the video generated two ideas: what would happen if you had two detector heads stacked? Would the gamma rays trigger both of them, or just the first one? I'm guessing both because if slate doesn't stop it, why would that thing stop it?
Also, can you pick up alpha particles on the other side of the slate? According to Earnest Rutherford, you should be able to. He says they will "quantum tunnel" through, which is just his way of saying he doesn't know how the alpha particles end up on the other side. So he just made up a verb for the process and went with it.
Lmao Osha recommends 2.5 mrems/hr for whole body, OSHA Limits: Whole body limit = 1.25 rem/qtr or 5 rem (50 mSv) per year (approx. 2.5 mrems/hr for all work hours). Hands and feet limit = 18.75 rem/qtr. Skin of whole body limit = 7.5 rem/qtr.
Super Takumaaaaaaaaar !!!
Let's recharge the camera with that reactor.
ps. most of thorium only emit alpha which can't penetrate your skin, so you are basically safe. But as you said, the dust could be dangerous. And It decays to radon which emit gamma, so you'd better to ventilate it often than just lock it up in the lead cage.
pps. thorium radiation still could damage your sensor because some isotope of thorium emit beta.
Is it ok if I use it on my a6400 occasionally? I'm scared of killing my camera lol
@@LanceRazon I believe it should be fine! Filters in front of the sensor should be dense enough to block most of it.
hello, thanks for your videos, I have a smc takumar 50mm f1.4 that the serial number is 6 million, but the glass looks clear, is it radioactive? thanks
got a geiger counter? Hehehehhe
hahaha, no, I have a baby at home, and my wife if telling me to get rid of it, its an m42 mount, I will trade it if anybody is interested.
I see that the SMC 50 f/1.4 is radioactive, but I may have the early version of Super Takumar with 8 elements, maybe that one is not.
Anyway...I love it!
what are adapting it to for use? you keep it on your digital ?
With digital Pentax K3 and the metal M42 adapter
you dont leave the lens on the camera do you? :)
No, I don't know, but I still hope that the older super tak is not radioactive. Or just a little bit.
The 8-element 50mm f/1.4 is NOT radioactive, according to what I've read. The improved refractive qualities of thorium glass allowed Asahi to make a cheaper, 7-element design that was as good as the earlier, very-expensive-to-manufacture 8-element design.
The 7-element f/1.4 has the red infrared focus mark on the depth-of-field scale to the left of '4', the 8-element lens has the red mark to the right of '4'. This is only true for the 50mm f/1.4 Super Takumar; I have no idea about any other lens models.
is the nikkor 80-200 2.8d radioactive?
ohh no, that lens isnt that old
What about the 55mm f2.0 with serial number of 7328855? It hasn't got a yellow cast to it tho
some of the 55mm later ones are not radioactive, nobody has an accurate serial date code for cut off
Theoria Apophasis Allright, thanks a lot!
That's fascinating... I have 3 of those ! I wish I had a geiger counter !
ahahahhaah, hope u dont sleep with em :P theyre HOT beta and gamma emitters
Well.... actually.... for the last few months they have been in one of the many little storage boxes crammed into bed room so they are no more than 6 feet from the bed ! ! ! Those little gammas possibly whizzing through my carcass as I write this.... plus not having funds for expensive new babies I carry one in camera pack at all times !
Is this lens dangerous to health?
it only takes a single corrupted cell to kick start cancer.
FACT QUOTE: The only naturally occurring isotope of thorium is 232Th and
it is unstable and radioactive. ... In addition to the alpha or beta
particles emitted as a result of the decay of a parent isotope, most of
the daughter isotopes also emit gamma rays.
who cares if the lense is radioactive. what ppl actually care about is if it affects them negatively and u didnt answer that q at all.
A useful and engaging group of videos on this topic, Thorium. Adorama has a vid, "4 Ways to Light a Face." Now, I'm counting 5.
;>)
I'll try live view on an external monitor instead of putting my eye near the radioactive source; the inverse square law applies, so the intensity of gamma radiation away from the tripod must be diminished, substantially. Tip: The inverse square law is more accurate if you put your studio inside a vacuum.
Geiger counter readings presumably can be taken for Nikkors with thorium (di)oxide, like, I hear, the 200mm f/4 and 22 other Nikkors I have, now that I think about it. Excuse me while I go buy a lead vault...
Well, now one has to choose between irradiation risk or lead-plated storage risk (for children) :)
the serious danger is if someone dropped this lens and it shattered, that DUST would basically make your home CONDEMNED
:/
how dangerouse does this radiation is ?
How do you store your radioactive lenses?
not next to my nuts.......
LMAO LOL HE HE LOL
what's the benefits of radioactive active lenses? very interesting
check out his videos back few days ago. It to preserve the trajectory of light, sort like a guardrail.
Please review those Takumars. pls!!! :)
i am, this week
let clear this out, in this Video you said " the radioactive of takuma 55 f2 start at serial over 1 milion" but in other your video you show 2 secret len auto takuma 55 f2 + yashica 5cm f2. The auto takuma 55 f2 serial start at 2xx,xxx then you said they are radioactive too. So what is the true ?
nobody knows the Xact serial number, just the general area
If those lenses were that radioactive, did they affect film somehow?
yes, if the film sat under it for long enough
Theoria Apophasis Does the same thing apply on the photographer behind the camera? Thanks!
Does the same thing apply for the photographer behind the camera? Thanks!
what's the equivalent chest xray esposure?
Extremity (arm, leg, etc) Xray: 1 mrem
Dental Xray: 1 mrem
Chest Xray: 6 mrem
Nuclear Medicine (thyroid scan): 14 mrem
Neck/Skull Xray: 20 mrem
Pelvis/Huip Xray: 65 mrem
CAT Scan: 110 mrem
Upper GI Xray: 245 mrem
Barium Enema: 405 mrem
so we have tow choises :P buy below that serial number for safety and decent pictures ish, or buy above that serial number risk it and get AWESOME radioactive Bokeh and awesome Bandiwth... mmm tough choice here :P haha
I have an asahi super takumar 55 1.8 here. serial 1617475. looks pretty yellow
really? i had another takumar at 1,750,000 that wasnt radioactive, but that was a SMC
maybe they changed it earlier on the super takumars to an earlier serial Hmmmmmm
well, it's a little yellow, does that necessarily mean it's radioactive? i'll keep it under my bed just to be safe XD
got a gieger counter? :)
nope, any other way to tell?
Ohad Pearl see if it warms your crotch after 10 hours of exposure,
KIDDING!!!! actually if you grow alfalfa sprounts under the lens, if radioactive theyll shoot up faster than lightning
I have a pentax but I checked it and it was not radioactive
Click Bait. These are not dangerous unless you are American and eat them.
If that radioactiveness kills fungus, I will use that to clean my other lenses.
Probably works for birth control also
So it's 13-15mR/hr beta radiation. Not great, not terrible!
Do the images look yellow?
nahh, ……you can clear that up with sunlight too
Definitely recommend this lens. Never knew you would test a Pentax lens!
ive had these lenses for ages.
Yay, Pentax finally gets its day in the sun! In fact, given the emissions, you might almost say the sun shines out of their rear elements, ha ha...
I have this model of lens, and the bokeh can be gorgeous. I also have the S1a film camera it came with. Epic, battery-free shooting all day long (as long as the film lasts), ably aided by my selenium-cell Sekonic light meter.
The height of mischievousness would be to sell them to greenie hipsters to adapt to their gazillion megapixel Sony cameras.
the takumars are EPIC TITS lenses, ive had them for ages, theyre great adapted to my FUJI
I can't remember if EPIC TITS is the top level or one below the cat's arse.
You love the lenses, now use the cameras. Borrow a K-1 if you can, shoot it against the D810, and tell us what you think. :)
top level
nonsense, im using adapted to a Fujifilm camera
Several people who've commented here clearly have *much* more experience with geiger counters (and accurate terminology). They've called into question his testing methodology and the implication that these lenses are inherently unsafe. Yet, I see no response at all. I've seen and learned from enough of his photography videos to conclude that he is indeed *amazingly* knowledgable about lenses -- yet, as has been pointed out, isn't familiar enough with the operation of a Geiger counter to accurately interpret what the readout is indicating. It's the lack of dialog that concerns me.. it's irresponsible to leave videos up in which the methodology has been debunked. At the very least I'd like to hear/see an update that takes this into consideration.
Ps im sure mR/hr means milliRad per hour, not milliRem. Anyways i had those lenses, i knew they were radioactive, but not SOOOO MUCH.
Not Milli Roentgen per hour?
I've got 3 of those.
If only you had a Pentax camera to mount that on.
ive got an adapter, i mount it on my FUJI
" Typical radiation levels can approach 10 mR/hr (100 μSv/h) as measured at the lens element's surface, decreasing substantially with distance; at a distance of 3 ft. (.9 m.) the radiation level is difficult to detect over typical background levels. For reference, a typical chest x-ray consists of about about 10 mR, a round-trip cross country airline flight exposes a passenger to 5 mR, and a full set of dental x-rays exposes the patient to 10 mR to 40mR. A study carried out by the Physics department of Sweden's Royal Institute of Technology estimates that total exposure to a professional photographer using a typical thoriated lens would amount to only 0.2% yearly allowable exposure to the eye and 0.17% to the whole body under the conservative standards of the Swedish Radiation Protection Authority. " source : camerapedia.fandom.com/wiki/Radioactive_lenses
fuck that i'm selling mine
😂 😂 😂
what's the benefits of radioactive lenses? very interesting
i made vids on the advantages over past few days
some lense reflective improvings