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Question about radioactivity..
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PostPosted: Fri Jul 09, 2010 10:45 pm    Post subject: Reply with quote
I've never heard of any radioactive Russian lenses but that's not to say one doesn't exist.

It's true there's not a definitive list of the kind of lenses we use which are radioactive, at least I've never seen one after searching for ages. Perhaps we could pool our knowledge and make one. I'll start off with some I know:

Super-Takumar 1.4/50 (2nd & 3rd versions - Part No 378 or 37801)
Super-Multi-Coated Takumar 1.4/50 (Part No 37902)
SMC Takumar 1.4/50 (Part No 37908)
Super-Takumar 2.0/35 (Part No 43931 with 49mm filter)
Super-Multi-Coated Takumar 2.0/35 (Part No 43932)
CZJ Pancolar 1.8/50
(not sure about the 1.8/80)

I think there are some Canon FD lenses with thorium, too. Everyone please add any more you know about.


PostPosted: Fri Jul 09, 2010 11:37 pm    Post subject: Reply with quote
peterqd wrote:

CZJ Pancolar 1.8/50


Mine (MC version) is not radioactive.

peterqd wrote:

I think there are some Canon FD lenses with thorium, too. Everyone please add any more you know about.


Canon FL 58mm f/1.2, 50mm f/1.8, 28mm f/3.5 and FD 35mm f/2 are radioactive, at least in some versions. FL 55mm f/1.2 is not radioactive (at least in some version).


PostPosted: Fri Jul 09, 2010 11:43 pm    Post subject: Reply with quote
JohnnyC wrote:

Oh, I was under the impression all of the old lenses had it, I'd rather get some lenses that aren't radioactive just to be overly safe.


To be overly safe, you should have your indoors radon levels checked. Seriously, radon is generally responsible for most of the typical person's radiation dose by far, and yet something can be done about it (e.g. move to a different location). Worrying about radioactive lenses is, in comparison, like worrying about the heat from a candle when you are sitting in a sauna. =)

(Also don't ever fly in an airplane; the dose of cosmic radiation in high altitude flight is very high compared to what you could expect from using thoriated lenses.)


PostPosted: Fri Aug 06, 2010 2:23 am    Post subject: Reply with quote
All,

Just wondering want happen when these radioactive lens go under x-ray machine at the airport?

Cheers,


PostPosted: Fri Aug 06, 2010 3:03 am    Post subject: Reply with quote
cheve wrote:
All,

Just wondering want happen when these radioactive lens go under x-ray machine at the airport?

Cheers,


Has anybody had or heard about problem with International shipment of radioactive lens setting off alarms?


PostPosted: Fri Aug 06, 2010 8:43 am    Post subject: Reply with quote
Basicly cant happen.
We are talking on very small doses.

First understand, everything is radioactive.
http://www.orau.org/ptp/collection/consumer%20products/consumer.htm
Read...


PostPosted: Fri Aug 06, 2010 10:25 am    Post subject: Reply with quote
What is bad for your health is reading all this crap about what is not good for your health - and if you beleive it all you may as well beleive that the moon is made of green cheese - mind you thats if you dont die of worry from reading all of that bullshit.
Life is hazardous, enjoy it whilst you can!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


PostPosted: Fri Aug 06, 2010 12:18 pm    Post subject: Reply with quote
Joosep wrote:
Basicly cant happen.
We are talking on very small doses.

First understand, everything is radioactive.
http://www.orau.org/ptp/collection/consumer%20products/consumer.htm
Read...


The doses from thoriated lenses may be small, but apparently it's considered high enough that it's not permitted to use thoriated glass in eyepieces:

Quote:
Perhaps the greatest health concern is the potential for thoriated glass to be used in an eyepiece. This is not permitted by the regulations, but it has occurred. If the eye is positioned close to a thoriated eyepiece, the dose to the eye’s outer tissues can be substantial.


Quote from your linked page.


PostPosted: Fri Aug 06, 2010 12:44 pm    Post subject: Reply with quote
trev wrote:
What is bad for your health is reading all this crap about what is not good for your health - and if you beleive it all you may as well beleive that the moon is made of green cheese - mind you thats if you dont die of worry from reading all of that bullshit.
Life is hazardous, enjoy it whilst you can!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


in a way it is true... but then if there are things that can be done to stop 'my' life terminate prematurely, I am all for it Very Happy

rant on: established facts based on proper science investigation(and research) is different from "believe". Sadly, in this age of web and all, a lot of believes are being sold as facts/truth...rant off Rolling Eyes


PostPosted: Sat Aug 07, 2010 3:31 pm    Post subject: Reply with quote
AhamB wrote:

The doses from thoriated lenses may be small, but apparently it's considered high enough that it's not permitted to use thoriated glass in eyepieces:


Firstly, the radiation does decreases by the square of increasing distance; even a few centimetres of distance drops the dose rate dramatically compared to surface of the radioactive element. Hence, even with the camera held to the eye and a highly radioactive lens attached, the dose to the eye remains very small, but holding a radioactive eyepiece directly to the eye would result in an order of magnitude greater dose. So with radioactive lens and eyepiece we are not talking about the same dose to the eye even if both are equally radioactive.

Second, radiation has different effect on different tissues, hence e.g. ICRP and EURATOM* regulations specify different occupational dose limits for different parts of the body (for the record, all of these limits are several orders of magnitude higher than the expected dose from radioactive lenses or eyepieces). For an area of skin the limit is much higher than for the lens of the eye—naturally the eye is more critical (and should also be protected from UV etc).

* See european council directive 96/29/EURATOM.


PostPosted: Sat Aug 07, 2010 3:37 pm    Post subject: Reply with quote
cheve wrote:

in a way it is true... but then if there are things that can be done to stop 'my' life terminate prematurely, I am all for it :D


By all means, but the effect of avoiding radioactive lenses is essentially negligible in your yearly dose of radiation. In fact, if you go outdoors to take photographs you might actually lower your dose from exposure to indoors radon… A much bigger effect on your radiation dose is never to fly and to move to a location with low natural background radiation.

For some reason practically no-one considers the radiation dose from high altitude flight when taking a trip abroad or measures the radon and radiation levels in their home, but the some people who would probably be shocked by the “truth” about these radiation sources are terrified by miniscule doses from photographic lenses—presumably because they happen to have read about this source of radiation and invisible radiation is scary and unfamiliar (even though it's all around us, all the time). (Note that this is not referring to you in particular, I'm just ranting in general. =)
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