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Radioactive lenses
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PostPosted: Fri Dec 25, 2009 10:45 am    Post subject: Radioactive lenses Reply with quote
Hi,

Does anyone know if Fujinon 55mm F1.8 containes radioactive thorium.

A lot of older lenses do but I am not sure about Fujinon.

Cheers,


PostPosted: Fri Dec 25, 2009 12:04 pm    Post subject: Reply with quote
Even if it would (what I don't know), the dose of radioactivity would be much lower than the one around you - test have proven that.


PostPosted: Fri Dec 25, 2009 12:54 pm    Post subject: Reply with quote
Can you eleborate on those tests?
My own tests do tell a different story ...


PostPosted: Fri Dec 25, 2009 2:16 pm    Post subject: Reply with quote
http://forum.mflenses.com/radioactive-lenses-t38,highlight,radioactive+lens.html

we had that discussion here several times....


PostPosted: Fri Dec 25, 2009 4:33 pm    Post subject: Reply with quote
My SMC Takumar 1.4 50mm (sold, yes) had radiation about 80x enviromental


PostPosted: Fri Dec 25, 2009 5:41 pm    Post subject: Reply with quote
Thank you semso Wink

http://yashica.org/254-2-Lens+radioactivity+-+measurements.html


PostPosted: Fri Dec 25, 2009 6:05 pm    Post subject: Reply with quote
To Snajper: My EBC Fujinon 1.8 55mm was free of radiation (sold).

To Cobalt60: You are welcome.

Yes , I have radiation detector. Most of lenses with radiation I sold or send to trash.
Only one I keep is yellowish Super Takumar 1.8 55mm (at distance of aprox. >50cm no traces of radiation).


PostPosted: Fri Dec 25, 2009 6:15 pm    Post subject: Reply with quote
Also famous CZJ Flektogon 2.8 35mm SILVER model was radioactive (my example)
I sended it to trash.


PostPosted: Fri Dec 25, 2009 6:18 pm    Post subject: Reply with quote
There are youtube videos...

Probably not too bad but watch out for a dusty lens from an atomic facility.

That stuff is widely dispersed:

http://www.dangerouslaboratories.org/rglass.html

http://www.nirs.org/alerts/02-02-2000/1

http://www.ratical.com/radiation/radMetalRecyc.html

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=389x4292098

Last edited by visualopsins on Sun Dec 27, 2009 6:55 pm; edited 1 time in total


PostPosted: Fri Dec 25, 2009 6:20 pm    Post subject: Reply with quote
What does this all mean? If I dont sleep with my lenses [excluding my Planar 1.4/50] will I be ok?


PostPosted: Fri Dec 25, 2009 6:40 pm    Post subject: Reply with quote
All my radioactive lenses (S-M-C 35/2, S-M-C 50/1.4, S-M-C 55/1.8, S-M-C 105/2.4 and 3 other radioactive Takumar I sell) are in my bedroom and I don't have a third arm or beeing shiny in the dark Laughing


PostPosted: Fri Dec 25, 2009 7:09 pm    Post subject: Reply with quote
Emissions could be 80x environmental 2mm from the lens rear element, but you are around the environment 24 hrs a day and you are rarely 2mm from the lens ever. Even carrying the lens on the camera puts you far from the radioactive source (inverse square law). Total additional dosage from a typical radioactive lens is very minor.

http://www.orau.org/ptp/collection/consumer%20products/cameralens.htm

They figure 0.7 millirem annually from normal use of a camera with a typical thorium lens, and up to 2 millirem for significant use, carrying it 30 days a year for 6 hours a day. I expect they are also making assumptions about the lens being carried close to the body.

NRC Occupational exposure annual limit is 5000mrem, and US average background radiation exposure is around 350mrem - so this exposure from thorium glass would be trivial.


PostPosted: Fri Dec 25, 2009 7:12 pm    Post subject: Reply with quote
Guess the question arose from carrying lenses long time in their trouser pockets by male photographers
wishing to have kids in future - that I would understand of course. I guess doing the same with a
cellphone for years seem to not interest anyone....it is not in the public focus like radioactivity. Since the
emitted radiation has a short max. reach, it should not be a problem having it in a room.

Btw. if there is so much care here about radioactivity and then dumping them into the trash without
any further though - is that really environmental friendly? Shouldn't they be disposed properly as special waste??

@Luis: thanks, that was the source I had in mind.


PostPosted: Fri Dec 25, 2009 7:20 pm    Post subject: Reply with quote
To Luisalegria:
80x environmental is not any TOTAL that is relativly: that means that every moment radiation from surface of the last inner lens from smc tak 1.4 is 80x bigger than radiation from Sun mesured at earth (West Europe region)
I made measurements with modern radiation detector. Also metal box do not
stop radiation from the lens (think about gamma rays)

That is my personal experance


PostPosted: Fri Dec 25, 2009 7:38 pm    Post subject: Reply with quote
Hi Semso -

Intensity is not the same as exposure. One has to consider the relevance of the measurement. 80x environmental measured from the rear element lens surface is going to be much less measured from the back of the camera body (@3-4 cm), probably undetectable from even 20 cm. Thats the inverse square law that applies to gamma radiation, it has nothing to do with material absorption and shielding. And then is the period of exposure, minutes or seconds only while close to the body/face. Thats why the danger can be considered low.


PostPosted: Fri Dec 25, 2009 7:52 pm    Post subject: Reply with quote
Maybe some over simplification has been here. I seem to recall, that thorium decays mostly into alpha-ratiation, which can no penetrate the skin (don't eat the stuff though). I was wondering, if it can penetrate the eye?

Beta and gamma - again, if I remember it right, are only minor players.

I do try to keep the SMC 50/1.4 not mounted into a digital camera when not in use (for an extended period). Better be safe than sorry.


PostPosted: Fri Dec 25, 2009 8:26 pm    Post subject: Reply with quote
I did work many years in a Nuclear Power Plant in radioactive zone, radioactivity was more higher than anybody can get lenses from ever even if living in a lens warehouse. In my personal opinion lens radioactivity case pretty much hysteria only. Klaus is doctor of physics if he say safe I believe it + my personal experience says human body is not hurt by small radioactivity.


PostPosted: Fri Dec 25, 2009 8:49 pm    Post subject: Reply with quote
There are no traces of histeria or to be scared.
There is one question?
Why should I use radioactive lenses if I can make the same quality photos with clean lenses?
By the way I am electronic engineer.


PostPosted: Fri Dec 25, 2009 8:58 pm    Post subject: Reply with quote
semso wrote:
There are no traces of histeria or to be scared.
There is one question?
Why should I use radioactive lenses if I can make the same quality photos with clean lenses?
By the way I am electronic engineer.


Why not use them ? Question is same. If not hurt anything ? Certainly we have many choices, but not use a lens just because it has small radioactivity that is same thing than not use microwave oven , cell phones etc. Risk is minimal really or no risk at all.


PostPosted: Fri Dec 25, 2009 8:59 pm    Post subject: Reply with quote
semso wrote:
There are no traces of histeria of to be scared.
There is one question?
Why should I use radioactive lenses if I can make the same quality photos with clean lenses?


Because some of the Lenses have individual "flair" and often a higher index of refraction, thats why Thorium was brought into glases ...
But the whole discussion is boring again and again. If you are worry about that.. dont discuss this.. sell your lenses.

Thorium is an Alpha emitter who is not able the permeat the dead parts of your skin. As long as you not use the lens as a child lollypop, there is absolutely no danger...

So if you have another opinion about that.. sell your lenses.

Either you will use the lens for her performance or not. In addition to that, the whole life is dangerous.. why? It ends with the dead Very Happy

The statements, made on yashica.org about his "tests" are stupid in my eyes.. sorry.

Cheers
Henry

Last edited by hinnerker on Fri Dec 25, 2009 9:33 pm; edited 1 time in total


PostPosted: Fri Dec 25, 2009 9:04 pm    Post subject: Reply with quote
Radioactivity from a Thorium lens is not a big deal. Most people are exposed to much more radioactivity than they would believe. One shouldn't forget that there are different categories of X-rays, some of them really harmless. As others here already had it pointed out, the radioactivity of Thorium lenses goes down very fast with distance. I'm much more afraid about having 2 nuclear plants 20 km around me.

As Klaus pointed it out, there is much more danger by cell phones than by lenses. Back in the early 90's it was given for sure that serving in a signals unit will give you much higher chances to get a cancer. Since them cell phones became a big business and now the same kind of waves got harmless. A miracle! I also observed (not scientifically proven, just an observation during 13 years of serving with radio equipments) that men serving as radio operators have more chances to have a girl than a boy compared to other soldiers. Strange, isn't it?

Edit :
If anyone here is scared about his lens, send it to me Rolling Eyes .

Last edited by Andreas on Fri Dec 25, 2009 9:10 pm; edited 1 time in total


PostPosted: Fri Dec 25, 2009 9:08 pm    Post subject: Reply with quote
Anybody knows the incidence (in %) of the radioactivity, in the amount that there are in lenses, in the appearance of diseases attributable to the radiation ?

It can be interesant to know what we are talking about not only in risk, but in concrete.

Rino.


PostPosted: Fri Dec 25, 2009 9:10 pm    Post subject: Reply with quote
hinnerker wrote:

Because some of the Lenses have individual "flair" and often a higher index of refraction

Cheers
Henry

+1

so is it ok if I only shower with my SMC 1.4/50 Tak?

Last edited by Bruce on Fri Dec 25, 2009 9:11 pm; edited 1 time in total


PostPosted: Fri Dec 25, 2009 9:10 pm    Post subject: Reply with quote
I don"t know which element in lens is radioactive (Thorium? or other?)
But, rays goes through metal
THAT ARE NOT ALPHA RAYS like most of people hopes?!


PostPosted: Fri Dec 25, 2009 9:12 pm    Post subject: Reply with quote
semso wrote:
Also famous CZJ Flektogon 2.8 35mm SILVER model was radioactive (my example)
I sended it to trash.


Wow, what a waste! I do not know why people are so scary about radiation, maybe partially affected by the movie or the story of Chernobyl......But anyway the radiation from lens is really not a big deal, if it is the government should have already stopped manufacturing the lens or importing them(and maybe you already had seen terrorist buying tons of lenses now). And the radiation is used a lot now days, you might know some of food was exposed under radiation environment to kill the bacteria and really don't want to count all the other usages of the radiation source.

Please look at the wiki for radiation:
http://en.wikipedia.org/wiki/Radiation

With the "normal" energy range of particles, the damage of radiation to human body is, when these kind of particles hits the nucleon, it might "kick out" electron of nucleon which will change the structure of the electrons distribution on the shell of nuclear, and the cross section(possibility) is very small. The biological effect of such kind of radiation is increasing the chance of having cancer, but not as big as smoking, look this page:
http://www.jlab.org/div_dept/train/rad_guide/effects.html

And also the radiation effect decrease as a function of 1/r^2, so within normal distance of using the lens will having even less effect.

If you are still worry about the radiation and prefer some more safe lens, then through the radiation lens to me Smile, I am a PH.D of nuclear and particle physics, we can make use of it Very Happy

By the way, as you have a radiation detector, send the radiative material to the trash is not the way you should do, it is not responsible for the others and not a good deed to do.
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