Home

Please support mflenses.com if you need any graphic related work order it from us, click on above banner to order!
SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

Radioactive lenses
Post new topic   Reply to topic
Home   Manual Focus Lenses
View previous topic :: View next topic  


PostPosted: Sat Dec 25, 2010 2:20 pm    Post subject: Reply with quote
they are not dangerous
http://community.livejournal.com/ru_pentax/34801.html


PostPosted: Sat Dec 25, 2010 7:46 pm    Post subject: Re: Radioactive lenses Reply with quote
vilva wrote:
It should be noted that even for a _serious_ photographer the dose received from a radioactive lens is rather insignificant,
an insignificant fraction of the natural background radiation. Smoking one cigarette per day gives
a larger extra radiation dose due to the radioactive polonium contained in the tobacco.

Veijo


Absolutely true. And flying in commercial airliners at high altitude gives nice big doses of radiation, too. This is why airline crews are up in arms about the full body scanners: they are already more irradiated than they should be.


PostPosted: Tue Sep 27, 2011 2:18 am    Post subject: Reply with quote
Sorry to dig up an old thread but I recently measured my Asahi Tak SMC 50 1.4 with a reader. Here's the video. As said earlier...it's a high reading next to the lense but as soon as I lift the Geiger Counter it drops big time. I'm not worried.

http://www.youtube.com/watch?v=q2FQhwPhWBw


PostPosted: Tue Sep 27, 2011 3:04 am    Post subject: Reply with quote
Excellent! As typical, exposure is reduced exponentially as distance is increased from the source. Something as low emitting as a camera lens becomes no issue when you consider the distance it will be from your face (has to be mounted on the camera!) and the limited time it will be there.

My Asahi 50/1.4 was one of my favorite lenses, but I sold it when I stopped using M42 lenses. The new owner said he's very happy with it.


PostPosted: Wed Sep 28, 2011 4:54 am    Post subject: Reply with quote
When I measured my 50mm f/1.4 S-M-C Takumar, it was only about 2/3 as radioactive as a Canon f/1.2 lens, and only 1/3 as radioactive as an old 1940's luminous dial watch.

All of these are way less radioactive than a 0.1 microcurie Strontium-90 Beta source that appeared in someone else's youtube video. Most people don't consider these radioactive lenses to be hazardous, even though they emit a fair amount of gamma.


PostPosted: Wed Sep 28, 2011 11:01 am    Post subject: Reply with quote
Anyone else think that guy is a proper tit for smashing up a 1.4/50 Takumar?


PostPosted: Wed Sep 28, 2011 11:13 am    Post subject: Reply with quote
How about background radiations ? From stones, wall bricks, even ground ?


PostPosted: Wed Sep 28, 2011 11:49 am    Post subject: Reply with quote
Attila wrote:
How about background radiations ? From stones, wall bricks, even ground ?


Supposedly there a few microcuries of radioactive potassium, uranium, thorium, radon, etc. in the average cubic meter of soil. Human bodies contain roughly 0.1 microcurie of radioactive potassium, depending on size.

Of course, you can't measure this radiation easily without special devices, because it's so spread out. The lens is a much more concentrated source. If the radioactive glass elements in a Takumar were as big as a person, the lens would be a lot more radioactive than the person.


PostPosted: Wed Sep 28, 2011 12:46 pm    Post subject: Reply with quote
iangreenhalgh1 wrote:
Anyone else think that guy is a proper tit for smashing up a 1.4/50 Takumar?

Goes without saying.


PostPosted: Wed Sep 28, 2011 4:09 pm    Post subject: Reply with quote
s58y wrote:
If the radioactive glass elements in a Takumar were as big as a person, the lens would be a lot more radioactive than the person.


But lot more smaller, I think this is same false problem like a scratch on lens.


PostPosted: Wed Sep 28, 2011 6:30 pm    Post subject: Reply with quote
Maybe we should put up a sticky about how all this talk about radioactive lenses is just stupid and nonsense?


PostPosted: Wed Sep 28, 2011 6:38 pm    Post subject: Reply with quote
iangreenhalgh1 wrote:
Maybe we should put up a sticky about how all this talk about radioactive lenses is just stupid and nonsense?


I think that will be unpolite I really don't want to hurt those people who beleive it this is a real problem. They have same right to beleive in it, than I have to don't .


PostPosted: Wed Sep 28, 2011 7:57 pm    Post subject: Reply with quote
Attila wrote:
I think that will be unpolite I really don't want to hurt those people who beleive it this is a real problem. They have same right to beleive in it, than I have to don't .
well that is nice of you attila, but you´re forgotting one thing. here we are in field of science and precise measurements, so it´s not a question of believe but question of measuring actual radioactivity emited from those lenses and comparing it to any other ussual emiter like cigarette or earth under us:)


PostPosted: Wed Sep 28, 2011 8:10 pm    Post subject: Reply with quote
I agree with berraneck.


PostPosted: Thu Sep 29, 2011 12:14 am    Post subject: Reply with quote
Me too.
Nothing to do with freedom of religion.


PostPosted: Thu Sep 29, 2011 12:36 am    Post subject: Reply with quote
I'd be more concerned about the radiation dose gotten from photographing mountains than from using any gear to photograph them (granite exudes radiation and mountains are higher in elevation, so the atmosphere filters less.)

That said, I will no longer sit for hours at a time with camera lenses on my lap. You know, so that in case I have kids they don't have extra arms and such.


PostPosted: Thu Sep 29, 2011 2:34 am    Post subject: Reply with quote
Lets put things in perspective:

My mother died recently aged 81, she was a heavy smoker and probably exposed to to more than average exposer to radiation. As far as I can tell from family records she is the the longest survivor. That includes those that were apparently more health concerned.

I think we all need to do a risk assessment -- sorry just been run over by a bus Shocked

I know its human nature to reduce the risk to our lively hood but please put in some perspective.

From a scientific point of view, radiation from the lenses we are taking about should pose a totally insignificant effect on our health. Well that's statistics, but maybe you would like to spend all your life contained within a lead line chamber consuming nothing produced outside.


PostPosted: Thu Sep 29, 2011 8:11 am    Post subject: Reply with quote
This is a very interesting thread.
So, no freedom to don't believe in science?


PostPosted: Thu Sep 29, 2011 10:45 am    Post subject: Reply with quote
I'm sorry for awakening the thread.


PostPosted: Thu Sep 29, 2011 11:13 am    Post subject: Reply with quote
pdesopo wrote:
This is a very interesting thread.
So, no freedom to don't believe in science?


Science is hard fact, no scope to believe or not believe with hard facts.


PostPosted: Thu Sep 29, 2011 11:58 am    Post subject: Reply with quote
iangreenhalgh1 wrote:
pdesopo wrote:
This is a very interesting thread.
So, no freedom to don't believe in science?


Science is hard fact, no scope to believe or not believe with hard facts.


Contemporary scientific thought is relative. Wink


PostPosted: Thu Sep 29, 2011 12:01 pm    Post subject: Reply with quote
The majority school of thought seems to be that the radiation dosage from thorium lenses (used as intended) is small compared to other things, like X-rays, jet travel, etc. Any health risk from lenses is minimal.

The minority school of thought is that any radiation from lenses is in addition to other sources, and poses some additional health risk, perhaps minor. All it takes is one unlucky gamma ray from a lens to start the chain of events leading to cancer. Since radioactive lenses are vastly outnumbered by non-radioactive ones, they're easily avoided. Besides, some radioactive lenses have to be de-yellowed periodically, unless you like the yellow tint.

I think both schools of thought should be respected. I'm no expert on radioactivity, and I've read many posts and articles by folks who know far more than I do. Some of these posts do support the minority school of thought, but most of them don't.


PostPosted: Thu Sep 29, 2011 12:03 pm    Post subject: Reply with quote
pdesopo wrote:
This is a very interesting thread.
So, no freedom to don't believe in science?

You question whether science is truth? Shocked Good or bad, if it wasn't for science we wouldn't know anything about radiation at all.


PostPosted: Thu Sep 29, 2011 12:13 pm    Post subject: Reply with quote
TBaker wrote:
I'm sorry for awakening the thread.

No need to feel that way. This debate will go on and on. Misinformation and downright lies have to be corrected.


PostPosted: Thu Sep 29, 2011 12:15 pm    Post subject: Reply with quote
That was the same point I was trying to make Peter.

This worry over radiation from lenses just leaves me shaking my head.
Post new topic   Reply to topic
Home   Manual Focus Lenses
Goto page Previous  1, 2, 3  Next
Page 2 of 3