Z250SA wrote: Lars Johnsson wroteWhat about all those ten thousends of people that used them every days for many years. And had them in the same room they where sleeping every day also. Never heard about anybody that got sick........None the less, you use past tense about them... It could, of course, be a consequence of Life itself, with a death rate of 100%.
Yes Canon stopped making and selling FD lenses many years ago So I suppose many people are dead that used them
morpheus2891 wrote:
... not smoking and eating healthy (organic for those of us in the US) is way more important for avoiding cancer then your choice of photographic lenses.
Indeed. I couldn't agree more, but I would have to say "beyond organic", since "organic" has been completely bastardized by the FDA so that Big Food can cash in and continue to control food.
(Good on you Germany, for banning that MON 810 !!!)
I've got an aero ektar that's got thorium (I think?) in it. At first I was conserned, but then I read up on how much is really in there, and it's not really anything to be worried about. Maybe if you built your house out of them, but not just having one
While I wouldn't worry to much about using a lens with this minute level of radioactivity, everyone who is saying 'don't worry' is glossing over the bit that it's your eye receiving the dose of alphas, which are normally stopped by the skin. It does matter how localized and where a does is delivered, as is evident in the bit above about smoking. Just something to keep in mind.
But yeah, this is a pretty tiny dosage. And we are still unsure if small dosages of radiation due contribute to cancer. There's the linear hypothesis and a competing view that says below a certain threshold, radiation isn't harmful (to very coarsely summarize). Again, this would be a TINY dose. A dose of 20 rem increases your chances of getting cancer by about 0.8%. The chances of dying of cancer from unknown causes is about 20%.
And living in Colorado compared to the east coast gives you a pretty big boost in background radiation. Just so you know. Might want to move :P
A lot of places list the radiation as alpha particles, which if you look at the Harvard link, you can see that the machine used wasn't particularly sensitive to alpha radiation. So this is likely gamma and beta radiation. Gamma can go through the metal on the end of the geiger counter. So that is a threat.
Personally I find the 3000 millirem a year for 80 years only increasing your risk by 10% rather hard to believe. I have seen claims in older textbooks that set the bar much lower to raise risk, I believe it was 70 some millirems to increase it by 2%, I'll have to check.
There are definitely jobs where you will likely get more at work than you would from a camera lens. But why would I want to raise my risk when I like zuiko lenses which don't tend to have thorium elements anyway? Plus I tend to carry lenses in my hand and pockets where doses would be higher. Like Aham said, I don't want the extra exposure, all of which is currently considered an extra risk to be avoided.
I read a lot on the internet, and a lot of it seemed crap. No surprise there I suppose. So I did a lot of research and thought I would share what I found. If you don't use lenses much, and don't carry them in your hand or pocket, you lower your risk. The numbers above are for that lens. If you have a more active lens, more risk.
If you have an active lens, you increase your radiation dose. If you have a really active lens, you increase it even more. And it varies, the same lens can have radioactive and non radioactive samples.
As far as why some and how many people get sick, that is a big subject, basically some people are more sensitive to a disease/pathogen some less. Then it depends on how much of that disease/pathogen one is exposed to as to your odds. So yes, I am sure some people used these for years and never noticed any trouble. I also suspect it harmed a few people, granted, a small minority.
I am rightly concerned about this, not paranoid. If people want to expose themselves to this, and know the risks, however small, that is fine. If they don't know the risks and get an ignorant exposure, that is a problem.
I would be interested to know how cellphones expose one to radiation. I was thinking these were microwave, which is a much longer and less powerful wavelength than gamma radiation.
Might be worth noting that the manufacturing processes that incorporated these isotopes into lenses were discontinued NOT because of the danger to worker or consumer from radiation but instead from danger of heavy metal toxicity (non radioactive) to workers in lens factories.
Aggressive use of hot lenses is like getting 5-10 chest X-rays a year, and few use their lenses that much. Also, that amount of radiation is not a big deal, especially small amounts over time.
By contrast, every time you have a CT-scan or heart stress test, you receive a dose of radiation that puts your lifetime odds of getting a lethal cancer at 1 in 1000. Sadly, most docs and even most radiologists don't know that and write ct scan orders as fast as dentists pass out lollipops.
I collect data at the Argonne accelerator a dozen or so times a year, but I am far more creeped out by what messages from outer space the white deer are getting by standing next to the giant satellite dishes than I am the radiation.
Didn't realize there was this much radiation exposure from smoking. Granted, the alpha particles don't travel far, although localized doses can be extremely high.
I do not believe you have to get anywhere near the ld50 to expose yourself to risks. Also, I would avoid carrying these in your pocket due to reproductive risks if you are of child conceiving/bearing age.
If people want to expose themselves to this, that is their business, but they need to be aware of risks. I stop short of saying I will never buy a radioactive lens, but at this time it seems unnecessary, although I do like old m42 gear.
We are exposed to radiation every day, and I don't know that I would go quite this far myself, but look around for yourself and see, all radiation exposure is currently considered a risk by different authorities. Caveat Emptor.
Todd, I knew somebody would think this! sebboh, the 55/1.2 has the potential to have this? might pass on that one or get it tested if I get one. I think it would be very difficult to get as much as a cat scan from a lens. And I think the cat scan would be more over the whole body.
Some people use their gear a lot around here I suspect, so thought I would bring it up. Seemed to be a lot of not so good stuff on the internet, Harvard and the Nureg document seem more reliable.
If scroll to the near the end of page 15, you'll see that the increase in cancer cases in men (for example) from a 0.1 gray dose (10 rem) is 800, resulting in 400 deaths. This is out of a 100,000 people, with the baseline cancer cases and deaths being 45,500 and 22,100 respectively.
Microwaves aren't ionizing radiation so they are much less worrisome then ionizing radiation like x-rays, etc.
The training I've received several times from health physicists at LLNL is that because α-emissions have such shallow penetration depths, they're pretty benign on the outside of the body--likely absorbed or bounced off the dead skin. On the inside they're like a bowling ball wreaking havoc. Gamma's on the other hand are likely to pass right through you, given their high penetration depths, but statistically do more harm.
AmbientMike wrote:
I do not believe you have to get anywhere near the ld50 to expose yourself to risks.
I don't think anyone would disagree with that statement. I think the LD50 dose is somewhere around 400 rem. No one is advocating dosages of 200 rem, 50 rem, 10 rem, or even 1 rem. 1 mrem (or less) is a bit different.
kidtexas: Why of course if I don't understand it it must not be true haha I'm not worried about 1 millirem, myself, although I suppose it is a risk, but if I got an extra 75 millirem/year off a lens, I'd worry. Although after reading that, wow, that is a massive dose, and seemingly small occurance, 800 extra out of about 45,000. If I read that table right, 45% of males will have cancer in their lifetime. Is that true?
Thinking microwaves are longer than visible light, which I'm exposed to all the time. UV probably much more dangerous. Plus I hate talking on the phone
Hmm, I might have extra access to the book since I'm at an academic institution. I quoted the relevant statistics though. Extra cases of getting cancer out of 100,000 from 10 rem is 800 (0.8% increase), extra cases resulting in death is 400 (0.4% increase). The baseline percentages of cancer is 44%/22% for cases/death.
Also: "At doses less than 40 times the average yearly background exposure (100 mSv), statistical limitations make it difficult to evaluate cancer risk in humans."