ampguy
Veteran
any owners measure them? How comfortable are you around them?
The oldest lens I have, a collapsible Summicron, is s/n 121... about a year past the Thorium versions, but I sitll plan to measure it.
The oldest lens I have, a collapsible Summicron, is s/n 121... about a year past the Thorium versions, but I sitll plan to measure it.
bmattock
Veteran
I probably have a few lenses which are mildly radioactive. I'm not planning to measure them or to do anything about them other than use them as lenses. I don't sleep with them under my pillow, after all.
People cheerfully eat genetically-modified food every day and worry about this? Seems like a waste of good time worrying to me.
Here's something that might be useful:
http://www.hps.org/publicinformation/ate/q1356.html
People cheerfully eat genetically-modified food every day and worry about this? Seems like a waste of good time worrying to me.
Here's something that might be useful:
http://www.hps.org/publicinformation/ate/q1356.html
JohnTF
Veteran
Immediately sell those lenses, cheaply. ;-)
I have heard of some that could make an autoradiograph.
Regards, John
I have heard of some that could make an autoradiograph.
Regards, John
ampguy
Veteran
Ok, so say 400x backgr doesn't concern anyone?
bmattock
Veteran
One transcontinental plane flight in the USA is 400x background radiation.
Alpha and beta radiation are easily absorbed and don't travel far. Gamma does, but there isn't much of it in those lenses. Don't eat them, don't sleep with them, and try not to hold the glass in direct contact with your eye.
But seriously, if it does bother you, I can understand taking precautions to include selling the lenses. Just because I'm not bothered, I do understand how others might be. Seriously, I can't seem to get people worried about eating genetically-modified food (which we all do now), and that happens to bother me a lot. So I get it. We just each have our own worries.
dogberryjr
[Pithy phrase]
I have an original Canon FD 55mm 1.2 ASPH which is supposed to have radioactive glass. I think all it does is add a nice, warm glow to color film. There was a thread on another forum where someone who was very familiar with radioactive materials said they were safe so long as you didn't grind up the glass and snort it.
summar
Well-known
I don't think there is anything to worry about using radioactive lenses. A Dutch photographer did some tests with the Industar 61 L/D lanthanum lens (standard on a FED 5) with reassuring results. Here's the link:
http://cameras.alfredklomp.com/fed5/radiation/
http://cameras.alfredklomp.com/fed5/radiation/
Roger Hicks
Veteran
Don't sleep with a stack of 'em under the bed (my Aero Ektar is in the back of a shed). Otherwise: don't worry.
I learned about radioactive lenses from Dr. A. Neill Wright who was co-author of the first paper on the subject, many years ago.
Cheers,
R.
I learned about radioactive lenses from Dr. A. Neill Wright who was co-author of the first paper on the subject, many years ago.
Cheers,
R.
charjohncarter
Veteran
I posted this for a cure of the yellowing:
The Super Takumar 50mm F1.4 (35MM) took about 20 hours. But my Super Takumar 105mm F2.4 (120) took 60 hours. It does work though.
The Super Takumar 50mm F1.4 (35MM) took about 20 hours. But my Super Takumar 105mm F2.4 (120) took 60 hours. It does work though.
ampguy
Veteran
Hi Brian
Hi Brian
How do you calculate your sentence below of 400x? From your own site provided, and the NRC site, I calculate about 0.25mrem/hour when flying at 30K feet, with variances during low and high solar periods.
Background radiation totals vary where one lives, etc. but average US # commonly used are about 360 mrem total per person per year.
This shows that flying might be giving you 10-20x the total radiation (radon, gamma, cosmic, internal, including averages for some medical procs).
One flickr user with a very early Thorium cron (92x...) measured 400x his background levels at the front of the lens. However, I don't know what his background was, maybe he was in a high background area for all I know from his flickr comments.
Anyways, thanks for understanding the concerns, and I hope you can show me where my math is wrong on the flying part.
We have studies on what % chances of getting cancer increased doses of radiation might provide, but I don't think we know all there is about GM crops, other than they're probably good for yields, and have a lot of currently unknown ramifications.
Hi Brian
How do you calculate your sentence below of 400x? From your own site provided, and the NRC site, I calculate about 0.25mrem/hour when flying at 30K feet, with variances during low and high solar periods.
Background radiation totals vary where one lives, etc. but average US # commonly used are about 360 mrem total per person per year.
This shows that flying might be giving you 10-20x the total radiation (radon, gamma, cosmic, internal, including averages for some medical procs).
One flickr user with a very early Thorium cron (92x...) measured 400x his background levels at the front of the lens. However, I don't know what his background was, maybe he was in a high background area for all I know from his flickr comments.
Anyways, thanks for understanding the concerns, and I hope you can show me where my math is wrong on the flying part.
We have studies on what % chances of getting cancer increased doses of radiation might provide, but I don't think we know all there is about GM crops, other than they're probably good for yields, and have a lot of currently unknown ramifications.
ampguy
Veteran
Cool
Cool
Great Roger, good to know your radioactive stuff is in the shed. I'm sure the neighbors feel better about that.
Cool
Great Roger, good to know your radioactive stuff is in the shed. I'm sure the neighbors feel better about that.
bmattock
Veteran
Sorry, I just grabbed it from some Google search, I could well be wrong. I seemed to recall it as something people said back when I used to travel for a living too.
bmattock
Veteran
And I think that's the problem; we don't know a lot, but we put it into the nation's food supply anyway.
So much is based on public perception, which can be nutty. For example, we allow any old kind of GM food into the food supply, and we don't even require manufacturers to label it so we can avoid it if we want to. And yet, we freak right out at the very notion of using radiation to sterilize food that cannot be pasteurized. Imagine that - we could put an end to those problems with lettuce and beef and so on (e coli and the like) RIGHT NOW but people are terrified of radiation. The fact that the radiation passes through the food and doesn't make it radioactive, nor does the radiation source ever come in contact with the food, doesn't impress them. They hear the word 'radiation' and that's all they care to hear, the answer is 'no'.
Yeah, I'll eat corn that has had fish DNA added to it, no problem, and you don't even have to tell me about it on the label. But don't sterilize leaf lettuce with radiation, I'd rather get e coli and die a horrible painful death on the toilet.
p.giannakis
Pan Giannakis
This is the only radioactive lens i've got
The measurements showed 300pcm when measured from the front element and 3.000pcm when measured from the back (obviously the radioactive element is on the back of the lens). I keep the lens on a Zenit 12XP body and the guy who measured the lens said that it is pretty safe as the radiation that actually goes through the back of the camera is less than 100pcm (which is very low).
The measurements showed 300pcm when measured from the front element and 3.000pcm when measured from the back (obviously the radioactive element is on the back of the lens). I keep the lens on a Zenit 12XP body and the guy who measured the lens said that it is pretty safe as the radiation that actually goes through the back of the camera is less than 100pcm (which is very low).
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Roger Hicks
Veteran
Great Roger, good to know your radioactive stuff is in the shed. I'm sure the neighbors feel better about that.
My nearest neighbours are further from the shed than I am. It's the far corner of what used to be my studio, 30-40m from my house, 60-100 metres from my neighbours. In my last house, I wasn't worried about 10m from the bedroom, 4m from the living room (or from the darkroom). I'd be quite happy with it in my new studio, 2-6m from the bedroom.
Cheers,
R.
K14
Well-known
I have an Aero Ektar 178mm, thorium type yellowish tint. I never measured mine, I don't sleep with it. I'm comfortable having it. I think there are more than just lenses that would be in the same boat, understand smoke detectors are radioactive too.
Cheers!
Gary
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Roger Hicks
Veteran
ampguy
Veteran
interesting
interesting
We learned a bit about GM by watching this PBS show:
http://www.pbs.org/thebotanyofdesire/potato-control.php
although I don't agree with everything in Michael Pollen's book "In Defense of Food"
Also there was a PBS show on how Monsanto was literally bullying farmers into using their stuff.
Back to radiation, it's interesting that the NRC (US's gov agency) doesn't care or control any of the medical devices (x-ray machines, CAT, PET, body scanners) because while these devices are the # 1 non-natural providers of radiation to the general public, the machines themselves don't contain radioactive material.
What's a dr. or dentist going to do - maintenance on their x-ray machines or go golfing??
interesting
We learned a bit about GM by watching this PBS show:
http://www.pbs.org/thebotanyofdesire/potato-control.php
although I don't agree with everything in Michael Pollen's book "In Defense of Food"
Also there was a PBS show on how Monsanto was literally bullying farmers into using their stuff.
Back to radiation, it's interesting that the NRC (US's gov agency) doesn't care or control any of the medical devices (x-ray machines, CAT, PET, body scanners) because while these devices are the # 1 non-natural providers of radiation to the general public, the machines themselves don't contain radioactive material.
What's a dr. or dentist going to do - maintenance on their x-ray machines or go golfing??
ampguy
Veteran
Correct
Correct
These are common sources of home radiation hot items, but the Coleman Thorium mantles were phased out in the early 90s, replaced by Yttrium. If you inhaled these, or kept them in your pocket for an hour or so, the estimation of radiation is ~200mrem, or over half a year's total radiation dose your body just absorbed.
If you scan the obituaries, you'll see a lot of folks dying of cancer were in the scouts, the scouts used these lanterns religiously.
Another common source of hot home items are old "Fiesta Ware" plates, coated in nicely colored uranium oxides, which many budget Geiger counter buyers use to test their new gadgets.
Correct
These are common sources of home radiation hot items, but the Coleman Thorium mantles were phased out in the early 90s, replaced by Yttrium. If you inhaled these, or kept them in your pocket for an hour or so, the estimation of radiation is ~200mrem, or over half a year's total radiation dose your body just absorbed.
If you scan the obituaries, you'll see a lot of folks dying of cancer were in the scouts, the scouts used these lanterns religiously.
Another common source of hot home items are old "Fiesta Ware" plates, coated in nicely colored uranium oxides, which many budget Geiger counter buyers use to test their new gadgets.
ampguy
Veteran
What's pcm wrt radiation?
What's pcm wrt radiation?
Does it relate or correlate to rems or Sieverts?
What's pcm wrt radiation?
Does it relate or correlate to rems or Sieverts?
This is the only radioactive lens i've got
The measurements showed 300pcm when measured from the front element and 3.000pcm when measured from the back (obviously the radioactive element is on the back of the lens). I keep the lens on a Zenit 12XP body and the guy who measured the lens said that it is pretty safe as the radiation that actually goes through the back of the camera is less than 100pcm (which is very low).