Thorium in my lens? nope.

[FilmOnly]

Please let me clarify...I do not own a Nikkor 50 1.4 S lens. However, I would like to conclusively verify whether or not that lens is radioactive. The brownish tint I see in photos of it gives me pause.

I have already owned Takumar lenses, and have tried the "window sill solution" suggested above. After doing this, I still did not feel comfortable in owning radioactive lenses, and thus I sold them. I have no interest in owning any other radioactive lenses, as, in testing them, some have found what would seem to be problematic levels of radiation...levels that would concern me. In another thread, I have provided a link for one such test. I do not claim to be a chemist or nuclear physicist. I am simply one who would rather be "on the safe side"--especially since there are many other fine lenses out there.

 

[Sirius Glass]

The amount of radiation in a lens is probably so low, that the background radiation from the bricks in your house or the wood in the furniture are very probably higher. Keep the lens, there are much higher source of radiation where you live and where you work.

Steve

 

[MikeSeb]

After doing this, I still did not feel comfortable in owning radioactive lenses, and thus I sold them. I have no interest in owning any other radioactive lenses....I do not claim to be a chemist or nuclear physicist. I am simply one who would rather be "on the safe side"....

You obviously are free to do as you wish. But this is one of the more ludicrously irrational things I've ever read on APUG.

I hope you don't smoke or drive a car, given the real risks those activities pose. Radon in your basement? Use sunscreen? Climb a ladder?

Good lord.

 

[FilmOnly]

MikeSeb: Your comments are offensive. You could have stated your opinion in a more civil manner.

Be advised that I have already cited a link for a test in regard to the relative harmfulness of the radiation in such lenses. The person who tested it found more radiation than what had been previously found (or assumed). After performing these tests, the person parted with his radioactive lenses. Once again, I choose to make no assumptions--especially since there are many fine lenses out there.

My position is certainly not irrational. It is better described as cautious. Camera equipment is not a necessity in life, and thus I prefer to err on the side of caution.

Your taking of the Lord's holy name in vain is also not appreciated.

 

[MikeSeb]

MikeSeb: Your comments are offensive. You could have stated your opinion in a more civil manner.

Be advised that I have already cited a link for a test in regard to the relative harmfulness of the radiation in such lenses. The person who tested it found more radiation than what had been previously found (or assumed). After performing these tests, the person parted with his radioactive lenses. Once again, I choose to make no assumptions--especially since there are many fine lenses out there.

My position is certainly not irrational. It is better described as cautious. Camera equipment is not a necessity in life, and thus I prefer to err on the side of caution.

Your taking of the Lord's holy name in vain is also not appreciated.

Wow. You read a lot into a short post. It's a rare day when I'm able to combine blasphemy AND incivility in one simple post.

I guess without the context provided by face-to-face contact, one man's blasphemy is another's frustrated skyward plea for reason to prevail.

Have a peaceful and radiation-free Thanksgiving.

 

[Ralph Javins]

Good morning;

Some perspective on the radiation levels of photographic lenses may be in order. Sort of.

A few years back testimony was being taken in Congress on the adjustment of the permitted radiation levels from nuclear energy electrical power generating plants. One of the gentlemen from the industry set a box down on the table near the microphone as he was beginning his testimony to the panel of Congressmen. After his prepared remarks, there were questions from the panel members. One of them asked about the box sitting on the table by the gentleman. His answer was that it was a scintillation counter; a high sensitivity "Geiger counter." Also, at that time, it was showing that the granite walls of the hearing room they were sitting in were emitting a radiation level approximately 2.5 times more than the level that the Congressmen were considering requiring the nuclear power plants to meet.

It is quite possible that our photographic lenses are not a significant problem. We seem to have been living with low level radiation of many different kinds for a few thousands of years now.

 

[totalamateur]

Probably depends on the lens...

I have a 24" aerostigmat where the rear element is supposedly as high as 30% by weight of whatever thorium component was used. From what I understand the 50mm takumars used a lower percentage. Also, the rear element of the 24" F6 is a little over 4 inches wide, and about an inch thick, so there's quite a bit more stuff there to emit Gamma, Beta, and Alpha particles. Some lenses used lanthanum as opposed to thorium, which does not emmit the more dangerous gamma radiation, jsut beta and alpha from what I understand. Someone (a radiation saftey officer who worked at a powerplant, can't find the link offhand) tested the AreoEktar (Aerostigmat?) 6 inch F2.5 and found that the radiaotion level 6 inches from the rear element was slightly higher than the "safe level" for prolonged exposure required at his plant, so basically, so long as you didn't sit on it for months, your future generations would be just fine. If I ever get my university buddies at the local physics lab to test my lens I will post the result. I might be slightly worried about it if I had one glued to my eye 12 hours a day 5 days a week.

For the record, I smoke, drink, drive a car with no airbags, I really don't think using my slightly radioactive lens is even on the top 100 list of things that's going to kill me. Pretty sure "murdered by jaded lover" or "accute toxicity to fixer" both have a higher probablility of landing on my death certificate.

 

[Pumal]

Ja...Ja...Ja!

 

[mrred]

Lead lined boxers would be a little heavy. My back hurts enuff already.

Imagine the stories we coul tell the ladies.......

 

[Fotoguy20d]

Also, at that time, it was showing that the granite walls of the hearing room they were sitting in were emitting a radiation level approximately 2.5 times more than the level that the Congressmen were considering requiring the nuclear power plants to meet.

Anyone here redo their kitchen recently? Did you put in granite counters? Try googling granite counters and radiation. Seems to me, someone will always find a way to tell you something is bad for you. Incidentally, what's the latest on soy? I've stopped paying attention to that one too.

I'm not sure I'd sleep with an aero-ektar under my pillow, and maybe I'd be reluctant to store it anywhere other than the basement (if I owned one), but I realy doubt a slightly radioactive lens is going to be the thing that kills me (I live in NJ after all)

Dan

 

[budrichard]

Regarding Budrichard's comment, Yes, I believe many civilian defense geiger counters have a check source, to validate the geiger counter is functioning, including my CDV-700. I did check the source prior for gamma and beta readings. Regarding my comment about it being from the 60's.... I don't know that this is in fact true, as I see a web site that sells and calibrates my same detector. Though it appears they haven't changed the design, construction or components inside since the ~60's. Regardless, I'm comfortable with the accuracy of the information provided on the particular lenses I listed.


To others, if it wasn't clear, after a few minutes of research on the subject, I'm not concerned. I suspect there is some truth in what Sanguestu brought up regarding risk is with manufacturers. Interesting factoid gleened was that in addition to improved refractive properties lenses, another use that thorium is sought after a potentioal replacement for uranium nuclear reactors, due to reduced waste.

I did find it fascinating how a discussion on radioactive lenses could quickly lead to over population. Ben must have a reputation ;-)

The check function is purely electronic and verifies if the meter responds to a current. Whether the GM tube is still functional and will generate a current is anyones guess without an actual radioactive source emmitting gamma rays which is what most of these GM counters were designed to detect.
In any event, this Thread is a 'Tempest in a Tea Pot'!
The NRC only regulates emissions from Power Plant and other facitlties that it has jurisdiction over. Your granite whether or not it has some low level of radioactivity is beyond its Regulation as are your lenses.EOT-Dick
BTW FWIW a Scintillation detector is NOT a high sensitivity GM detector.
A GM detector works by counting a pulse from a gas discharge breakdown when a particle with sufficient energy enters the GM tube. A Scintillation detector records the light pulse from a particle interacting with a crystal of material that gives off light.

 

[Mackinaw]

I remember reading, years back, that the real risk with using thorium in a lens is in the manufacturing phase. I guess thorium dust in the factory (grinding phase of lens building) can pose a significant and real health risk to the worker.

Jim B.

 

[John_Nikon_F]

With respect to Nikon lenses having thorium, it was, IIRC, only the early multicoated lenses, like the Nikkor-N 35f1.4 and Nikkor-N 28f2.
The 50f1.4 Nikkor-S is only single coated, and just happens to have a brownish color tint to the coating. If you hold one up to your eye, then look at a light source, it's perfectly clear. A 35f1.4 Nikkor-N, that is yellowed, not so much. It'll actually look yellow from the thorium.

I had one of the early 35f1.4's, and it was a decent lens, just got tired of using a Nikon B8 filter to correct for the yellow tint, while shooting daylight balanced color film. I guess I could've just shot tungsten balanced color film with it outdoors, then had normal looking photos...

If I ever come across another early 35f1.4 that still has normal colored thorium glass in it, I'll grab it, and use it just like I do my other Nikkors. Really not that big a deal to me.

-J

 

[Raphael]

Wow...

Hello everyone,

I see that this subject brings so much passion here, even on an rather civilized place like APUG

I am suprised too, to see so much unargumented, unchiffred point of views, and so much "the man who saw the man who saw the bear" stories (I don't know if this french expression translates well into English)

To be straight, I owned and I own several radioactive lens, and a (recent/calibrated) radiameter (Geiger counter), so I know *de visu* what is the point.

The top winner is an old Super-Takumar 105 mm f/2,4 (for Pentax67), where the rear cell read at contact about 1500µRem/h (micro-rem by hour) or using the normalized unit 15 µSv/h (micro-Sievert by hour).

I had to borrow another radiameter from a friend to measure it, since mine was saturated ! (Max is at 999µRem/h).

This measure should be taken for the two type of radioactivity, beta AND gamma. Because gamma radiations are emitted by this lens too. Beta radiations are stopped by any screen, even by the human skin. But Gamma rays are another story, a few millimeter of solid matter are virtually transparent to them. I still measured about 600µRem/h through a 5 mm thick lead sheet, in contact.

To make comparison, I measure next 20µRem/h in my basement. This measure is more than the outside in open air (a few µRem/h), because I live in a granite walls house, in an granitic ground region. So why bother about granite sink ? . So we can state this SuperTakumar is almost one hundred more radioactive than natural background.

I found the Pentax 50mm f/1.4 (for 35mm camera) Super-Takumar was radioactive, too, about 300/400µRem/h at rear lens. I think it's the same glass which the Pentax 67 Takumar used, but the lens is much smaller in 35mm, too.

I tested three of them, and the three was hots

A good clue for a *possible* radioactive glass is a certain brownish cast increasing with age, under a certain incidence. Don't mix up it with yellowing of aged optical glue, which can occurs with older lens.

The better way to see it to hold the lens in front of a white sheet of paper. It's less visible if you look at a light source.

In my "horror box" I have too a German lens (from a well know maker , where the rear lens is radioactive (but much more lesser), and the front lens of a well know French camera. And no, NONE of my russian lenses are radioactive (and I own a good number of them)

A notion that should not be forgotten is that radioactivity decrease like light, in inverse square law of distance. For example, the 67 tak radioactivity is indiscernible from the background at 60 or 70 cm of distance.

So, dangerous, or not ? An arbitrary safety limit, in Europe, for the civilian people was put at 1mSv/year (100mRem/year). So, with a rough calculation, you should be *in contact* with the above Takumar about 66 hours to exceed that yearly safety limit. So, don't sleep with one of these under your pillow Or even on your bedside table.

Yes, when you expose yourself to radiations, you'll take an increased statistical risk to develop a cancer, but when you smoke too (IMHO, a bigger risk), when you are X-rayed at the hospital or the dentist, or even worse, if you receive a PET-scan, or when you take an high altitude transatlantic flight (cosmic rays), etc, etc.

It's each to his own, to decide if this risk should be taken (and added), nobody should be blamed to take on side or the other

The better work I know on the net, about gamma lenses was made by Michael Briggs, on a rational, depassionated way :here

An interesting image, about film fogging, can be seen in this thread

Sorry for this lenghty post, and sorry too for the many probable english mistake.

Regards,

Raphael

 

[FilmOnly]

This is an excellent and informative post, Raphael. What you have noted is all I was trying to point out:

"The top winner is an old Super-Takumar 105 mm f/2,4 (for Pentax67), where the rear cell read at contact about 1500µRem/h (micro-rem by hour) or using the normalized unit 15 µSv/h (micro-Sievert by hour).

I had to borrow another radiameter from a friend to measure it, since mine was saturated ! (Max is at 999µRem/h)"

"So we can state this SuperTakumar is almost one hundred more radioactive than natural background."

I am glad you have discussed this matter in an in-depth manner, as no one seemed to believe me when I had tried to explain that there is more than "a little" radiation in some of these lenses. I agree: for some this may be tolerable, but others are not "irrational" for being concerned and cautious and thus avoiding these lenses.

 

[Uncle Goose]

LOL, all those people who are worried about radiation of thorium show that they don't have the slightest clue how radiation works. Take a geiger counter and measure the inside of your house, then measure the lens, It might not even be detectable trough the background radiation you receive every single moment of your life. Also, the particles it emits are Alpha and Beta particles, while Beta particles are a little more powerful they cannot go trough things like thick lens glass, nor can the alpha's. Both particles are only dangerous when they float freely in the air as dust.

Keep in mind that people can have far more dangerous substances in their homes. Remember those old vintage wall clocks that glow in the dark?? well if they are old enough (like WWII area or just beyond that) they most likely contain Radium, and that dear people is a real Gamma emitter!! Far more powerful and dangerous then Thorium used in lenses. I have 2 tabs (which they used to place above the light switches in the 1960's to see the switches in the dark) filled with Radium and while the emissions don't go very far (I use them to test Geiger counters that are part of my NBC collection) I don't want that to float around in the form of dust (the Radium in the tabs I have are safely sealed in Plexiglass). The most dangerous part of radioactivity is when it's released in the form of dust, then it can get everywhere, when it's in the glass it can go nowhere.

 

[budrichard]

"LOL, all those people who are worried about radiation of thorium show that they don't have the slightest clue how radiation works. "

And I suppose your credentials are degrees in Physics, Nuclear Engineering or are we reading the comments of a degreed Health Physicist?
Other than those three disciplines I would suggest that individuals refrain from Posting what they 'think' and only what they 'know' to be fact concerning isotopic emmiters, the physical effects and biological effects.
I commented once but just don't have the time nor inclination to address all the mis-statements.-Dick

 

[polyglot]

"Ever been to Utah? Ra-di-a-tion. Yes, indeed. You hear the most outrageous lies about it. Half-baked goggle-box do-gooders telling everybody it's bad for you. Pernicious nonsense! Everybody could stand a hundred chest x-rays a year. They ought to have them, too. When they canceled the project it almost did me in. One day my mind was full to bursting. The next day - nothing. Swept away. But I'll show them!"

 

[Uncle Goose]

"LOL, all those people who are worried about radiation of thorium show that they don't have the slightest clue how radiation works. "

And I suppose your credentials are degrees in Physics, Nuclear Engineering or are we reading the comments of a degreed Health Physicist?
Other than those three disciplines I would suggest that individuals refrain from Posting what they 'think' and only what they 'know' to be fact concerning isotopic emmiters, the physical effects and biological effects.
I commented once but just don't have the time nor inclination to address all the mis-statements.-Dick

At least I did some serious research instead of letting myself make scared by the media and others the don't know squat about it. Most people are like sheep, they just take in whatever they see from the media, I on the other hand do a lot of reading and even inform myself with people who actually work with radioactive products. And what exactly was wrong with my post to begin with?? did it contain any lies?? NO IT DIDN'T! Thorium breaks down in the Alpha and Beta spectrum, not the Gamma or X-rays. Radium does emit Gamma rays, so that's not wrong either. The amount in those lenses are small and they are encapsulated in the glass, so unless you break the glass there is nothing to worry about. Of course radioactive compounds are not toys but in the Post Chernobyl era people are way too scared because the media pictured some grotesque misconceptions about nuclear radiation.

 

[One_DaveT]

The check function is purely electronic and verifies if the meter responds to a current. Whether the GM tube is still functional and will generate a current is anyones guess without an actual radioactive source emmitting gamma rays which is what most of these GM counters were designed to detect.

It's not a "check function" that I'm refering to, but rather a check source. The check source, is a small sealed radioactive substance stuck on the side of the detector. The nuclear physics professor I bought this from told me what the substance was, but now I forget.... actinium maybe.

 

[jime11]

"One day my mind was full to bursting. The next day - nothing. Swept away. But I'll show them!

From one of my all time favorite movies!!!

 

[budrichard]

It's not a "check function" that I'm refering to, but rather a check source. The check source, is a small sealed radioactive substance stuck on the side of the detector. The nuclear physics professor I bought this from told me what the substance was, but now I forget.... actinium maybe.

If a radioactive isotope. it has a half life i.e. after a certain amount of time only one half will be left to disintegrate and provide readiation to check your GM tube. Therefore you need to know the isotope and half life to determine if the source is still effective in checking your GM. In short, just having a GM counter without the proper documentation and/or training, you don't really know if your detecting anything.-Dick

"At least I did some serious research instead of letting myself make scared by the media and others the don't know squat about it. Most people are like sheep, they just take in whatever they see from the media, I on the other hand do a lot of reading and even inform myself with people who actually work with radioactive products. And what exactly was wrong with my post to begin with?? did it contain any lies?? NO IT DIDN'T! Thorium breaks down in the Alpha and Beta spectrum, not the Gamma or X-rays. Radium does emit Gamma rays, so that's not wrong either. The amount in those lenses are small and they are encapsulated in the glass, so unless you break the glass there is nothing to worry about. Of course radioactive compounds are not toys but in the Post Chernobyl era people are way too scared because the media pictured some grotesque misconceptions about nuclear radiation. "

I never said anything was wrong with your Post. I was merely trying to ascertain your credentials. Your statements actually lead me to believe you had none in this area. Now that may be good and that may be bad. It's up to you to make that determination but to make the statement "in the Post Chernobyl era people are way too scared because the media pictured some grotesque misconceptions about nuclear radiation" shows an incomplete understanding about the subject and the dangers. My last statement still stands:
"Other than those three disciplines I would suggest that individuals refrain from Posting what they 'think' and only what they 'know' to be fact concerning isotopic emmiters, the physical effects and biological effects.
I commented once but just don't have the time nor inclination to address all the mis-statements"
-Dick

 

[One_DaveT]

If a radioactive isotope. it has a half life i.e. after a certain amount of time only one half will be left to disintegrate and provide readiation to check your GM tube. Therefore you need to know the isotope and half life to determine if the source is still effective in checking your GM. In short, just having a GM counter without the proper documentation and/or training, you don't really know if your detecting anything.-Dick
-Dick

Yes, this is all pretty common knowledge for anyone with a little interest. No, you do not need to know the isotope and half life for a check source. I think you have an inverted view of how to use a check source. If as you imply, a radioactive isotope with a very short half life was used as standard check source , and disentragated long before my test, the result would be that the check source test would not register. This opens up the possibility of a false-negative, i.e. a dead detector that's not actually dead. However, there is no room for a false-positive, as you are concerned, i.e. a working detector that is actually dead. What can not be done with an unknown check source, is to callibrate the actual reading.

I'm not really clear on what's driving this bad detector discussion. As I mentioned earlier, regarding the 1960's quip, I don't believe it to be the case. My detector was last callibrated in 1996, and it's a model that can be bought on-line today. Do you have one of the lenses that I have listed and believe it to be radioactive?

 

[budrichard]

"Do you have one of the lenses that I have listed and believe it to be radioactive?"

Nope, but I do have Trinitite, sand fused by the first Atomic Bomb blast and graphite from Chicago Pile Number One(CP1), the first Reactor.
I don't spend my time worrying about these or lenses as there is real stuff to worry about.-Dick

 

[MikeSeb]

Thorium-232 has a half-life of 14.05 billion years, which---though it's about the age of the universe---is still apparently shorter than the half-life of this tedious thread.

@FilmOnly, when you fixate on minuscule risks that have virtually no chance of harming you, while you daily engage (I presume) in other activites that pose orders-of-magnitude higher risks to you without giving them a thought (you DO drive a car, no?), then, sorry, yes, that IS irrational. behavior.

Now, you are perfectly within your rights to engage in irrational behavior that doesn't harm others; but don't call it something it's not, and expect to go unchallenged.

Here expireth my half-life. I'm out.