Thorium Oxide Lenses

Peter7100

Senior Member
Does anyone know if there is a definitive list of Nikon lenses that contain Thorium Oxide?
I have seen a few lists online but they are definitely not complete but only what they have tested.
I know there is an agruement that the amount of radiation emitted is minimal but it would be nice to know what older lenses do not contain Thorium Oxide.
 

Bikerbrent

Senior Member
This is from https://www.diyphotography.net/can-radioactive-lenses-harmful-health/

Okay, time to get serious. A radioactive lens containing Thorium emits around 0.01 mrem/hr. For comparison, a chest X-ray emits 10 mrem, and none of us died from it. According to Nuclear Regulatory Commission, Americans on average receive 620 mrem each year. So, even if you had your Thorium lens with you at all times (and I assume you’re not that attached to it), you’d receive a yearly dose of 87.6 mrem from it.


In conclusion – no, you can’t get sick or die from radioactive lenses. You’d have to spend months in a room filled with 2 million of them in order to feel any consequences, and I believe no one’s collection is that big. So, if you have a couple of good ones, don’t be afraid to use them.
 

Peter7100

Senior Member
This is from https://www.diyphotography.net/can-radioactive-lenses-harmful-health/

Okay, time to get serious. A radioactive lens containing Thorium emits around 0.01 mrem/hr. For comparison, a chest X-ray emits 10 mrem, and none of us died from it. According to Nuclear Regulatory Commission, Americans on average receive 620 mrem each year. So, even if you had your Thorium lens with you at all times (and I assume you’re not that attached to it), you’d receive a yearly dose of 87.6 mrem from it.
In conclusion – no, you can’t get sick or die from radioactive lenses. You’d have to spend months in a room filled with 2 million of them in order to feel any consequences, and I believe no one’s collection is that big. So, if you have a couple of good ones, don’t be afraid to use them.


I have seen counter arguments suggesting they could be unsafe in certain situations. I suspect that unless every single lens that contains Thorium was properly tested we can't assume they are all safe.
Imagine the scenario where Thorium was used for food packaging or childrens toys, then I think there would be lists everywhere showing which items contained it.
I tend to agree that the chances of these lenses causing an issue are extremely low but it would still be nice to see a definitive chart where people were able to make their own choice to buy or not. I can confirm my collection will never be 2 million unfortunately :D
 

Fred Kingston

Senior Member
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I have seen counter arguments suggesting they could be unsafe in certain situations. I suspect that unless every single lens that contains Thorium was properly tested we can't assume they are all safe.
Imagine the scenario where Thorium was used for food packaging or childrens toys, then I think there would be lists everywhere showing which items contained it.
I tend to agree that the chances of these lenses causing an issue are extremely low but it would still be nice to see a definitive chart where people were able to make their own choice to buy or not. I can confirm my collection will never be 2 million unfortunately :D

THERE's your solution... Don't buy any old lenses... just buy the new ones. YOUR choice. :unconscious:
 

Woodyg3

Senior Member
Contributor
I'll never argue against being careful about potential health hazards. There was a time that we all thought asbestos was perfectly safe, for instance. That said, I suspect that most of us are getting a good deal more radiation from natural sources like soil and minerals in drinking water than from a camera lens.
 

Danno

Senior Member
I just did a quick google search and the EPA said that the material was used in camera lenses from the fifties through the seventies. The best way to identify the lenses is that they will have a yellow tint to the lens that will darken over time having a negative effect on the images produced. A little fun fact from DP review...

A radioactive lens that contains thorium will give off approximately 0.01 millirem (mrem) per hour. By comparison, a chest X-Ray gives you 1,000x that dose in a single shot (about 10 mrem). That means it would take you 167 days of using the lens for 6 hours per day before you've exposed yourself to a single X-Ray's worth of radiation.

The EPA was not concerned about the health risk either unless you were using an eye piece.

https://www.epa.gov/radiation/what-kinds-consumer...
Older camera lenses: some camera lenses from the 1950s-1970s incorporated thorium into the glass, allowing for a high refractive index while maintaining a low dispersion. The health risk from using older camera lenses is low; the radiation received when using a thoriated lens camera is approximately equal to natural background.​

It is always a matter of choice but it seems that the lenses changed from thorium to other types of glass that were more stable. I know that does not completely answer the question, but it does give you a time line and a color to look for. As for me I am not one to chase after old glass that much, but if I did I am thinking I would not be as concerned, but that is me... I used to ride a motorcycle with no helmet.
 
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