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SMC Takumar 55 f1.8 radioctive?
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PostPosted: Wed May 04, 2011 1:17 am    Post subject: Reply with quote
estudleon wrote:

Everything that we can add to our knowledge is a good thing. And more when the health can be involved.


I wouldn't really classify radioactive lenses as a health concern. Frequent amateur use of radioactive lenses would, in sort of a worst case scenario, result in a dose equivalent to a single airplane flight (or 2-6 days of “normal living”). In practice I doubt that anyone on this forum comes even close to that figure because the radioactive part is almost always in the rear element group*, shielded inside the camera body, and the fraction of time spent using radioactive lenses in a way that puts them close to the user is only a small part of all time spent on photography.

Here's a little chart about radiation doses; taking a photowalk with a radioactive lens is about comparable to eating a banana:
http://xkcd.com/radiation/



* Another question out of curiosity: does anyone know of a lens where the radioactive element is not in the rear of the lens (i.e. dosimeter reading is higher in front than rear). I know only one, Fujinon 100mm f/2.8.


PostPosted: Wed May 04, 2011 11:13 am    Post subject: Reply with quote
Quote:
In practice I doubt that anyone on this forum comes even close to that figure because the radioactive part is almost always in the rear element group*, shielded inside the camera body,


For the Olympus f/1.4 and Canon f/1.2 lenses, most of the radiation comes out the front element:

Olympus:
http://www.youtube.com/user/uyt384#p/a/u/1/gkh0bEdjiFY

Canon:
http://www.youtube.com/user/uyt384#p/a/u/0/TrS4bCfnn6Q


PostPosted: Wed May 04, 2011 11:50 am    Post subject: Reply with quote
The common assumption has been that most of the radiation emmitted by Radioactive lens elements was relatively harmless Alpa partcles, which cannot even penetrate a piece of paper, let alone human skin.
Given a lack of evidence to the contrary, the assumption seemed correct.
This has led to a completely lax and blaze attitude among those that bought radiocative lenses, unaware they were radioactive, only to discover later that they were.
However, they are completely underestimating the danger they are in through Beta and Gamma radiation being emmitted from their lenses.
This video proves the original assumption to be completey wrong, and dangerously so! Shocked :

http://www.youtube.com/user/uyt384#p/a/u/0/TrS4bCfnn6Q

...Still want hang onto that "hot" glass?

Last edited by DSG on Wed May 04, 2011 7:08 pm; edited 2 times in total


PostPosted: Wed May 04, 2011 12:26 pm    Post subject: Reply with quote
Quote:
This video proves the original assumption to be completey wrong, and dangerously so! Shocked :


The purpose of these videos was not to cause shock and alarm, but rather to compare the relative amount of radioactivity from these 3 lenses. I did mention the difference of opinions on the danger at the end of each video, so I hope everyone does their own research on the issue, and comes to their own conclusions. The readings fall off very quickly with distance, and the readings fall to background levels just a few to several feet away from the lens.

Also note that the readings were taken with a simple pancake probe Geiger tube. This unit is really just a survey meter, and not a dosimeter, and may exaggerate the measured counts compared to background. I think you need a special type of scintillation counter that mimics the absorption of gamma rays by tissue, if you want to assess the heath risks of these lenses.

Note that I have no credentials whatsoever when it comes to radioactivity and health issues, so take what I have to say here with a grain of salt. (I do keep these three lenses in a far corner of he house, though Smile )


PostPosted: Wed May 04, 2011 1:40 pm    Post subject: Reply with quote
DSG wrote:
The common assumption has been that most of the radiation emmitted by Radioactive lens elements was relatively harmless Alpa partcles, which cannot even penetrate a piece of paper, let alone human skin.


Who assumed this? I've seen this discussion come up on this forum many times and this is the first time I hear someone claiming it's only alpha.


DSG wrote:

Given a lack of evidence to the contrary, the assumption seemed correct.


Whenever someone measured the radiation with a dosimeter, there was evidence to the contrary.

DSG wrote:

However, they are completely underestimating the danger they in through Beta and Gamma radiation being emmitted from their lenses.


It seems to me from these discussions that people are overestimating the danger.

DSG wrote:
Still want hang onto that "hot" glass?


Yes, please. If you don't, I will pay postage for you to ship your radioactive lenses to me. =)

If you have moral issues with giving me these lenses, you can be comforted by the fact that I live in Finland where the natural background radiation is higher than in many other countries, and I could significantly decrease my total radiation intake by moving to, say, England (although if I went there by flying I would get much more of a dose during the flight than I do in a year of using radioactive lenses). Yet I choose to stay here (for now, for completely unrelated reasons).


PostPosted: Wed May 04, 2011 8:34 pm    Post subject: Reply with quote
Arkku wrote:

DSG wrote:
The common assumption has been that most of the radiation emmitted by Radioactive lens elements was relatively harmless Alpa partcles, which cannot even penetrate a piece of paper, let alone human skin.


Who assumed this? I've seen this discussion come up on this forum many times and this is the first time I hear someone claiming it's only alpha.).


Where have you been lately?...The recent Japanese nuclear disaster spurned numerous debates on the dangers of radiation exposure.
Perhaps not on here but certainly on other forums.

Arkku wrote:
DSG wrote:

Given a lack of evidence to the contrary, the assumption seemed correct.


Whenever someone measured the radiation with a dosimeter, there was evidence to the contrary.)


I dont recall anyone measuring so much radiation from a lens before whilst ensuring that they blocked out any alpha particles with a plastic cap first!

Arkku wrote:
DSG wrote:

However, they are completely underestimating the danger they in through Beta and Gamma radiation being emmitted from their lenses.


It seems to me from these discussions that people are overestimating the danger.


Or perhaps its just you that is under estimating them? Wink


Arkku wrote:

DSG wrote:
Still want hang onto that "hot" glass?


Yes, please. If you don't, I will pay postage for you to ship your radioactive lenses to me. =).


As far as I am aware I dont currently have any radioactive lenses but if I find that I do, they will be be safely disposed of by deep burial in the ocean depths...Selling them on would be like giving someone cancer!


Arkku wrote:

If you have moral issues with giving me these lenses, you can be comforted by the fact that I live in Finland where the natural background radiation is higher than in many other countries, and I could significantly decrease my total radiation intake by moving to, say, England (although if I went there by flying I would get much more of a dose during the flight than I do in a year of using radioactive lenses). Yet I choose to stay here (for now, for completely unrelated reasons).


I very much dought that a geiger counter on an aircaft at normal commercial passenger flying altitudes would register as much radiation as that blasting out the front of that FD 55mm f1.2 Asperical! Shocked


PostPosted: Wed May 04, 2011 9:29 pm    Post subject: Reply with quote
Arkku wrote:


estudleon wrote:

So, why the yellow single element of the yellowish lens is cleared when I put it under the sun (UV rays, no?).

This is a question that I never seen answered clearly.

Only one element, not cement yellowish, so what happen?


I don't actually know what exactly causes the yellowing, but it seems clear that whatever it is that turns yellow in or on the glass can be re-bleached by UV. However, UV does not “reverse” radioactive decay… Which is why some people claim that UV “can not” cure yellowing, even though it obviously can—therefore it seems obvious that the yellowing is not a direct consequence of materials changing due to their radioactive decay but rather something else that is “yellowed” by radioactivity and bleached by UV.


Irradiation of many glasses causes the formation of so-called colo(u)r-centres or F-centres (German Farben) whose name is self explanatory. The radiation can be external or can come from the decay (gamma) of a glass component or impurity. Colouration can occur in a single glass element without the need for any sort of glass cement. The colour can often be bleached by UV radiation, or by heating.


PostPosted: Wed May 04, 2011 10:08 pm    Post subject: Reply with quote
Thanks John

But my question was relative to the affirmation about the possibility that the lenses become yellow, by causes different of the radioactivity.

Always thought that the yellow lenses was caused only by the radioactivity.
If not, nor was the cement who made the yellowish in the lens, because the element was lonely, so why?


PostPosted: Wed May 04, 2011 10:11 pm    Post subject: Reply with quote
DSG wrote:

Where have you been lately?...The recent Japanese nuclear disaster spurned numerous debates on the dangers of radiation exposure.
Perhaps not on here but certainly on other forums.


Yes, and no-one said “radioactive lenses only give alpha radiation”. Why would that even be related to Fukushima?

DSG wrote:

Arkku wrote:

Whenever someone measured the radiation with a dosimeter, there was evidence to the contrary.)


I dont recall anyone measuring so much radiation from a lens before whilst ensuring that they blocked out any alpha particles with a plastic cap first!


Most dosimeters are built with the alpha-blocking plastic cover already in place. It's often non-removable, e.g. the plastic housing of the entire unit.


DSG wrote:

Or perhaps its just you that is under estimating them? :wink:


Well, I have measured the radioactivity of all my lenses (got a new one today, turns out it, too, was radioactive, yay!).

I have also read up extensively on the subject of radioactive doses, and including research on radioactive lenses done by nuclear safety authorities, and compared the estimated doses from these articles to my own measurements, and concluded that compared to 1) living in Finland, and 2) flying in an aeroplane a couple of times a year, the even the worst case doses pale in comparison. So I consider it over-reacting to start worrying about a lens that gives you less of a dose than one flight in an aeroplane when I wouldn't give it a second thought if someone offered me a free flight to a place I want to photograph.

And I have also personally contacted the Finnish radiation safety authority, and received a reply that lens radiation is nothing to worry about.


DSG wrote:

As far as I am aware I dont currently have any radioactive lenses but if I find that I do, they will be be safely disposed of by deep burial in the ocean depths...Selling them on would be like giving someone cancer!


You should also bury bananas then (they contain radioactive potassium). Not to mention cigarettes. Or medical x-ray machines.

But seriously, please, please, please, please do not destroy any lenses. Radioactive or not. No matter how worried you are personally, that would be seriously overreacting.

(Also, just to be safe for you and the lenses, stay away from the Fujinon range.)


DSG wrote:

I very much dought that a geiger counter on an aircaft at normal commercial passenger flying altitudes would register as much radiation as that blasting out the front of that FD 55mm f1.2 Asperical! :shock:


Aircraft flight gives about 3-7µSv/h depending on the altitude and latitude (normal background radiation on ground being 10-30 times less). This dose is received over the whole body. Meanwhile, some readings for the most radioactive lens I have (Minolta Rokkor 58mm f/1.2), alpha blocked, by distance from rear element:

0.1 cm: 8.5 µSv/h
2 cm: 5 µSv/h
5 cm: 2 µSv/h
10 cm: 1 µSv/h
20 cm: 0.4 µSv/h
Mounted on camera, measured from back of camera: 0.7 µSv/h

Background level in my apartment at the moment, in another room on the other side of the building, no radioactive materials nearby: 0.17 µSv/h

Background radiation is of course also present in the lens measurements, and has not been subtracted. The figures given here are rough measurements I did just now while writing this, and I reset the dosimeter between measurements.


Looking at how the radiation from the lens diminishes by distance, we can see that if you were to hold the lens close to your body, the area directly touching the lens (on the rear side of the lens) would receive a dose roughly equivalent to spending the same time in an aircraft flying at 12 km. Other areas of the body would receive significantly lower doses. In practice this will never occur, as there will always be the camera bag and/or the camera itself in the way. The highest actual dose would only be around 5 times background to a very limited area—you could not get your whole body close enough to the lens even if you curled up in fetal position with the lens in the middle.

Considering the time we are actually using radioactive lenses out of all lenses we have, and the time those lenses are actually in close proximity to our body, the doses are negligible in comparison to unavoidable background radiation.


There was an article, I think NUREG-1717 if I recall correctly, by the US Nuclear Regulatory Commission, estimating the doses for television camera operators who would professionally stand behind a television camera every working day, and their estimate for the “most radioactive lens allowed by regulations” (which, in practice, cannot be found for “civilian” use) was 200-600 µSv per year. In comparison airline crew gets about 3,000-9,000 µSv per year, coal miners 700 µSv, and single mammograph would give also around the 700 µSv. A CT scan would give several times that.

Seeing as small format photographic lenses are smaller than television camera lenses, they don't contain the maximum permitted amount of thorium (as per the same report), and no-one here uses radioactive lenses several hours per day, every day (and indeed very few are lucky enough to be using any lens several hours per day ever day), the doses from that are significantly lower. The same report estimated something of a “worst case” scenario at 20-60 µSv per year, around the same as one flight, but I sincerely doubt anyone here will even come close to that.


I can accept if someone says that they will not permit any unnecessary radiation, fine, that's their choice, but I cannot accept talking about these lenses like they were an automatic cancer giver, and much less can I accept anyone destroying lenses out of ignorance. Please read up on the subject before you stir up panic—don't just trust me, I suggest getting some perspective e.g. from:

http://www.unscear.org/unscear/en/publications/2000_1.html

and

http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1717/

Last edited by Arkku on Wed Jan 29, 2014 7:57 am; edited 1 time in total


PostPosted: Thu May 05, 2011 12:21 am    Post subject: Reply with quote
Arkku wrote:
DSG wrote:

Where have you been lately?...The recent Japanese nuclear disaster spurned numerous debates on the dangers of radiation exposure.
Perhaps not on here but certainly on other forums.


Yes, and no-one said “radioactive lenses only give alpha radiation.


Now I think about it, it may have been Beta radiation as the topic came round to how the photographer could get eye damage, or even go blind, from radiation from Radioactive lenses leaking through the viewfinder.

Arkku wrote:

Why would that even be related to Fukushima?.


Because the disaster stimulated much discussion and debate on the whole topic of radiatioactivity and its effects on the human body.

Arkku wrote:

DSG wrote:

Arkku wrote:

Whenever someone measured the radiation with a dosimeter, there was evidence to the contrary.)


I dont recall anyone measuring so much radiation from a lens before whilst ensuring that they blocked out any alpha particles with a plastic cap first!


Most dosimeters are built with the alpha-blocking plastic cover already in place. It's often non-removable, e.g. the plastic housing of the entire unit.


Perhaps, but I've never seen results like that with the cap on before. Shocked

Arkku wrote:

DSG wrote:

Or perhaps its just you that is under estimating them? Wink


Well, I have measured the radioactivity of all my lenses (got a new one today, turns out it, too, was radioactive, yay!).


You are obviously one of those with a lax and blaze attitude towards the subject I mentioned before. Rolling Eyes

Arkku wrote:

I have also read up extensively on the subject of radioactive doses, and including research on radioactive lenses done by nuclear safety authorities, and compared the estimated doses from these articles to my own measurements, and concluded that compared to 1) living in Finland, and 2) flying in an aeroplane a couple of times a year, the even the worst case doses pale in comparison. So I consider it over-reacting to start worrying about a lens that gives you less of a dose than one flight in an aeroplane when I wouldn't give it a second thought if someone offered me a free flight to a place I want to photograph.

And I have also personally contacted the Finnish radiation safety authority, and received a reply that lens radiation is nothing to worry about.


But they would of course, would'nt they...I mean their hardly likely to tell you anything that would cause you to panic and run to the nearest news reporter so you can tell him him how your lenses made you grow an extra ear! Laughing

Arkku wrote:

DSG wrote:

As far as I am aware I dont currently have any radioactive lenses but if I find that I do, they will be be safely disposed of by deep burial in the ocean depths...Selling them on would be like giving someone cancer!


You should also bury bananas then (they contain radioactive potassium). Not to mention cigarettes. Or medical x-ray machines.


What?...Do medical X-Ray machines contain Bananas? Very Happy

Arkku wrote:

But seriously, please, please, please, please do not destroy any lenses. Radioactive or not. No matter how worried you are personally, that would be seriously overreacting.

(Also, just to be safe for you and the lenses, stay away from the Fujinon range.)


Dont worry, I'm only kidding...I'm aware of the lists of the well known radiocative lenses so I will simply do my best to avoid every lens listed on them.
I'm very curious about the FL 55mm f1.2 though as it never comes up in such lists, yet the earlier FL 58mm f1.2 does and the later FD versions too...Ever tested the FL 55/1.2 for radiation?


Arkku wrote:
DSG wrote:

I very much dought that a geiger counter on an aircaft at normal commercial passenger flying altitudes would register as much radiation as that blasting out the front of that FD 55mm f1.2 Asperical! Shocked


Aircraft flight gives about 3-7µSv/h depending on the altitude and latitude (normal background radiation on ground being 10-30 times less). This dose is received over the whole body. Meanwhile, some readings for the most radioactive lens I have (Minolta Rokkor 58mm f/1.2), alpha blocked, by distance from rear element:

0.1 cm: 8.5 µSv/h
2 cm: 5 µSv/h
5 cm: 2 µSv/h
10 cm: 1 µSv/h
20 cm: 0.4 µSv/h
Mounted on camera, measured from back of camera: 0.7 µSv/h

Background level in my apartment at the moment, in another room on the other side of the building, no radioactive materials nearby: 0.17 µSv/h

Background radiation is of course also present in the lens measurements, and has not been subtracted. The figures given here are rough measurements I did just now while writing this, and I reset the dosimeter between measurements.


Looking at how the radiation from the lens diminishes by distance, we can see that if you were to hold the lens close to your body, the area directly touching the lens (on the rear side of the lens) would receive a dose roughly equivalent to spending the same time in an aircraft flying at 12 km. Other areas of the body would receive significantly lower doses. In practice this will never occur, as there will always be the camera bag and/or the camera itself in the way. The highest actual dose would only be around 5 times background to a very limited area—you could not get your whole body close enough to the lens even if you curled up in fetal position with the lens in the middle.

Considering the time we are actually using radioactive lenses out of all lenses we have, and the time those lenses are actually in close proximity to our body, the doses are negligible in comparison to unavoidable background radiation.


But a camera bag or a camera cannot stop gamma radiation...And thats the most damging kind to our DNA.
It is the DNA damage caused by exposure to radiation, whether that is UV light, Alpha particles ingested through sources such as smoking, eating Bananas, or breathing Radon for instance, or via external sources like radioctive lenses or nuclear fallout, that can lead directly to deseases like Cancer and Leukemia. Seriously. I'd rather limit my dose to zero and if avoiding radioactive lenses helps me achieve that then thats what I'll do. Wink


PostPosted: Thu May 05, 2011 12:56 am    Post subject: Reply with quote
DSG wrote:

I'm very curious about the FL 55mm f1.2 though as it never comes up in such lists, yet the earlier FL 58mm f1.2 does and the later FD versions too...Ever tested the FL 55/1.2 for radiation?


Yes, my FL 55mm f/1.2 is not radioactive.


(Ignoring the rest of your post as you clearly ignored mine.)


PostPosted: Thu May 05, 2011 2:01 am    Post subject: Reply with quote
I worked with a lot of different radioactive materials. As Arkku said it's not as poisonous as most people think, if it's handeled correctly.

Don't chew and eat your lens and everything will be fine! Laughing

And look at the advantages, the radiation should prevent any fungus Laughing



BTW: I personally have a tiny amount of tritium meltet with a yellow fluorescent into glas as an unique key fob to find any keyholes in the dark for the next 20 years. Maybe I will build a brighter gadget from an old lens If I can get one cheap. Smile Idea

Last edited by ForenSeil on Thu May 05, 2011 2:16 am; edited 1 time in total


PostPosted: Thu May 05, 2011 2:15 am    Post subject: Reply with quote
ForenSeil wrote:

And look at the advantages, the radiation should prevent any fungus Laughing


or create monster mutant fungus which will invade the world! Shocked Shocked Laughing


PostPosted: Thu May 05, 2011 2:30 am    Post subject: Reply with quote
Quote:
I dont recall anyone measuring so much radiation from a lens before whilst ensuring that they blocked out any alpha particles with a plastic cap first!


In the video, I think the radiation looks worse than it really is. The pancake probe mica window is round and almost the same size as the front of the Canon lens, so it sees a good fraction of the radiation coming out. Also, this geiger tube is not very sensitive to gamma radiation, so the background looks low (some 1000x less than the reading at the front of the lens.)

If you want to get a truer picture of the damage done to human tissue from this lens, you need something that can give reliable uSV/hr readings (like Arkku reported for his lenses). The Geiger counter in the video can be switched over to uSv/hr (or mRem/hr), and shows from 78-86 uSV/hr at the front of the lens blocked only by a sheet of paper. The uSv/hr readings from this Geiger counter are based on a Cs137 source (if I read the manual correctly), and could be way off for this lens. It's unclear what the real uSV/hr dose measured by a true dosimeter would be for a source like this lens, where the radioactivity comes mostly from thorium and its decay products.


PostPosted: Thu May 05, 2011 2:50 am    Post subject: Reply with quote
Why does food and drink prepared over a wood fire taste so good?

Is there a difference between food cooked in a microwave oven and food cooked in wood-fired brick oven?

Is there a difference between exposure to natural background radiation and exposure to refined and concentrated particulate dispersed in air, on land, in food, or on lens coatings? I know three sisters in their 60s who as young children played in uranium mines with the dust that made their skin glow -- they are all healthy still beauties with big families, grand- and great-grandkids. Is uranium in situ matrix less toxic or even beneficial compared to the refined product of known toxicity?


PostPosted: Thu May 05, 2011 2:55 am    Post subject: Reply with quote
I'm far from being an expert, but from the little I learned from readings, Uranium, in it's natural state of unprocessed metal, is only very slightly radioactive, probably even less than the thorium in the lenses.
It becomes lethally dangerous when processed for industrial use (civil or war)


PostPosted: Thu May 05, 2011 5:05 am    Post subject: Reply with quote
Orio wrote:
I'm far from being an expert, but from the little I learned from readings, Uranium, in it's natural state of unprocessed metal, is only very slightly radioactive, probably even less than the thorium in the lenses.
It becomes lethally dangerous when processed for industrial use (civil or war)


Nope! Uranium is very very toxic, it doesn't matter much if it's natural or enriched or deriched etc. A few mg of an uranium-salt would be deadly anyhow. When ingested it's heavy metal character is not much less dangerous than its radiation. An natural uranium is also very radioactive.

When it's in it's metal form it's pretty safe.


PostPosted: Thu May 05, 2011 6:55 am    Post subject: Reply with quote
ForenSeil wrote:

And look at the advantages, the radiation should prevent any fungus :lol:


I did have fungus in one radioactive lens, though, but it was on the other side of the 600mm lens. =)

(Maybe I should complain that the lens is not radioactive enough…)


PostPosted: Thu May 05, 2011 1:57 pm    Post subject: Reply with quote
Radioactive fungus and esporas are dancing in your room??


PostPosted: Thu May 05, 2011 5:12 pm    Post subject: Reply with quote
At least I protect the environment by saving electricity since the blue glow from my lens cabinet makes such a beautiful night-light.


PostPosted: Wed Jan 29, 2014 7:30 am    Post subject: Reply with quote
I own my radioactive Super Tak 55mm since 1970 . I could survive and be a member of this nice forum.


PostPosted: Wed Jan 29, 2014 11:10 am    Post subject: Reply with quote
I'd forgotten all about this excellent discussion, which I think does get to the reality of radioactive lenses, which is why my Auto Tak' 55 is sitting in the window instead of the bottom of the ocean.
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