Kodak Ektar Aero 2.5 radioactivity

Discussion in 'Large Format Cameras and Accessories' started by Marco B, Jul 26, 2008.

  1. Marco B

    Marco B Member

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    Hi all,

    I don't own one, nor would have a camera to match it, but I have read before here on APUG about the ultra fast Kodak Ektar Aero 2.5 lenses for aerial camera's dating back to WWII, and I know that some of you probably own one.

    In recent times they seem to have gotten a bit of "cult" status due to their nice bokeh when used as portrait lens.

    However, there is the question of the radioactivity of the Thorium containing lens elements, and this is the reason for this post.

    In last month's edition of the Dutch photo magazine "Camera Magazine", there is an article by Stefan Heijendael, who, after seeing a intriguing advertisement for a 2.5 lens for 4x5 photography, decided to buy one.

    Of course, as a good father of two kids, knowing the lens was radioactive didn't chear up himself and his family. He therefore created a do-it-yourself lead covered storage box, but of course as with all matters related to the invisible phenomenon of "radioactivity", the small nagging question kept crawling in the back of his head "Is this enough, and do I actually need to worry at all??"

    So he contacted the University of Maastricht here in the Netherlands, where the medical department was willing to help.

    So here it is: some real measurements of the level of radiation emitted by such a lens. Better know what you have stored in your seller! :wink::

    - At 10 cm from the back of the lens (it's the back lens element containing the Thorium additions), they measured 1.3 microsievert / hour

    - At an weekly exposure of 4 hours year-round, this sums up to 270 microsievert in one year.

    - The amount of Thorium was estimated to be 36kBQ.

    So now the author of course wondered "Is that dangerous?" :surprised:

    Our Dutch government uses a maximum of 1000 microsievert / year as an acceptable dosage of radiation to which members of the public may be exposed. The report made up by the medical department therefore concluded that there was "No significant elevated risc", that based on moderate 4 hours weekly usage.

    Now on another note, according to this link:

    http://encyclopedia.farlex.com/Microsievert

    "Humans can absorb up to 0.25 Sv without immediate ill effects; 1 Sv may produce radiation sickness; and more than 8 Sv causes death."

    Well, since 1 Sv is 1000 times the accepted year dosis of 1000 microSv, I guess death of owning a Ektar Aero is really not imminent... :D

    Remained just one question by the author Stefan Heijendael, was his lead box completely senseless? Answer: No, 1 mm of lead reduces exposure by a factor of about 20, so if the lens is stored in such a box at more than 1 meter of a subject and with long time exposure, there are no significant riscs from having the lens around in your house...

    Well, lastly, since Stefan included it as well, here's the disclaimer :D:

    The department of radiology of the University of Maastricht, the author (Stephan) and I guess myself :tongue:, do not take any responsibility for negative health effects of owning, storing and using such an Ektar Aero lens. No rights can be obtained based on the measurements. The measurements are based on just a single specimen of this type of lens, and radiation levels may vary...
     
    Last edited by a moderator: Jul 26, 2008
  2. Photo Engineer

    Photo Engineer Subscriber

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    Apropos to this but a bit off-topic, dye transfer paper contains Thorium as well.

    PE
     
  3. Marco B

    Marco B Member

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    Well, that's an interesting one PE, why does dye transfer paper contain Thorium? I've never handled the stuff, is it transparent and also makes use of the refractive properties of Thorium, as in the Ektar lens?
     
  4. Ian Grant

    Ian Grant Subscriber

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    Some 60's f1.4 and faster SLR lenses used radioactive glass, f1.4 Takumars were one. A few other high speed lenses have similar glass.

    We live with radiation all the time, and even going for a walk can expose you to it. My sister died from a rare cancer only seen in patients exposed to radiation fallout, she regularly walked in an area (in the UK) contaminated by fall out from Chernobyl. The farming restrictions are still in place today.

    Ian
     
  5. Pinholemaster

    Pinholemaster Member

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    I own 3 Aero-Ektar lenses. I do not store them between my legs. HA!

    Many buildings built of granite release far more radiation to the occupants. Living in high mountain regions of the world expose one to huge levels of radiation.
     
  6. Marco B

    Marco B Member

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    Ian, what extremely sad to hear, that's the Chernobyl disaster getting way to close... and now with the short sighted renewed "push" for nuclear energy to "save" the planet, do we ever learn?
     
  7. Tom Hoskinson

    Tom Hoskinson Member

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    All of you who own Aero Ektars (and/or Apo Lanthars) and are concerned. Ship your lenses to me and I will safely dispose of them.:tongue:
     
  8. Mark Layne

    Mark Layne Member

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    The Radon gas in your basement will kill you long before any lens I know of
    Mark
     
  9. Phillip P. Dimor

    Phillip P. Dimor Member

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    I definitely agree that radon is a more realistic threat to ones self and family.
    I remember reading somewhere that an astronomer snapped up a surplus aero ektar for use as an eyepiece(?).. The results after several years were not good from what I recall but I wish I could find the original quote of this.

    Personally me, I think i'd rather find a Graf Variable Anastigmat or a Pentac and save the weight but that's another thread.
     
  10. Photo Engineer

    Photo Engineer Subscriber

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    Thorium used in dye transfer paper was there as a white colored mordant that tied the dyes in place. The Thorium cation (positive ion) formed a very insoluable salt with the anionic (negative) sulfonic acid dyes used in dye transfer. In the last instant product that Kodak was going to introduce, they used Nickel as the salt for assisting in both complexing and mordanting the dye in place. That improved dye stability as well.

    So, metals, and radioactive materials have a long history in photo products.

    PE
     
  11. Marco B

    Marco B Member

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    I agree Radon gas is an issue. I remember that I once got an e-mail of someone working at an environmental agency in Norway. He wanted some help on an issue with determining a statistical relationship between soil / rock types and measured Radon levels in houses. Now I'm neither an expert on statistics or radioactivity, but I had developed a highly automated tool in a much used Geographical Information System (the GIS program ArcView by ESRI, the "Microsoft" of the GIS IT world) that allowed you to interpolate measurements like that. That's why he came to me.

    Anyway, back to your remark: Although the measurements showed no immediate concerns with moderate usage of 4 hours / week, a cumulative exposure of an unprotected Ektar lens 24 hours a day, 365 days a year at close proximity, WILL cross the 1000 microSV safety zone as determined by law.

    It's probably not without reason many of these old lenses show a brownish radiation damage to the lens, as described by Michael Briggs here:

    http://home.earthlink.net/~michaelbriggs/aeroektar/aeroektar.html

    So, all in all, I would keep it stored safely when not in use...
     
  12. Matthijs

    Matthijs Subscriber

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    And don't store all your films next to it!
     
  13. Marc Akemann

    Marc Akemann Subscriber

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    I have an old Minolta 28mm f2.5 MC W. Rokkor SI lens that apparently was manufactured with rare earth elements (lanthanum & thorium). The glass has yellowed and I've read (in the following link) that exposing the lens to UV light can help remove that. I haven't tried to remove the yellowing, but, this is simply a fantastic lens with b&w film. One of my favorites.

    There is some interesting info here regarding radioactive Kodak lenses, among others: http://www.camerapedia.org/wiki/Radioactive .

    Marc
     
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  15. Ole

    Ole Moderator Staff Member Moderator

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    Marco, I agree with you on th erelative "dangers2 of Aero-Ektar use and fondling.

    But I would be extremely sceptical about interpolating anything to do with the bedrock of Norway. I've worked here as a geologist for 25 years, and there are daily surprises! I think Statens Strålevern might need a little bit more geological competence in their numbers - if the oil boom ends, I'll send them a note. :wink:
     
  16. amuderick

    amuderick Member

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    I wouldn't worry at all about this level of radiation. To quote from the Health Physics Society position statement on radiation:

    "There is substantial and convincing scientific evidence for health risks following high-dose
    exposures. However, below 0.05–0.10 sV (which includes occupational and environmental
    exposures), risks of health effects are either too small to be observed or are nonexistent."

    The measured dosage you listed is 0.00027 sieverts.

    Don't forget that the existing regulations which limit exposure aren't the levels at which the danger starts. They are the values where danger starts divided by some very very large fudge factor! In your case, the Netherlands government chose a fudge factor (safety factor) of 50x.
     
  17. Ole

    Ole Moderator Staff Member Moderator

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    There are fudge factors, and then there are safety factors...

    Basically, there are three different kinds of effects of radioactivity: Acute, accumulated, and genetic. Or "somatic, teratogenic and genetic", depending on which report you read.

    All that says is that there is a certain dose which is very likely to make you sick, which has unfortunately been determined rather precisely through the nuclear bombs of Hirosima and Nagasaki, and the firefighters of Chernobyl.

    Then there is a lower dose which will eventually make you sick, as in increasing the risk of cancer at a future time.

    Then there's the dose that might might make your children sick, or their children again, or...

    As I wrote we have a fair idea of the acute dose. But 60-odd years is far too short a time to have any idea about the "safe" dose levels for the other effects - only that there might be one.

    Interestingly there is a study that seems to indicate there might actually be a minimum safe exposure too, which makes people receiving at least some radiation healthier than those who live an extremely "screened" life. :wink:
     
  18. John Kasaian

    John Kasaian Member

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    I had my Aero Ektar checked by the nuclear medicine department at the local hospital and got similar results. Just for curiousity they also tested the lens in the home made box I constructed and it blocked all measurable radiation and so that is what I store it in.
    What is it? A 6"x6" x6" cardboard postal carton lined with pieces of "Wonderboard" a cement impregnated fiberglass backing left over from when I installed a tile floor in the kid's bathroom.
     
  19. nc5p

    nc5p Member

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    With all the radiation detectors all over the highways (Albuquerque has a bunch on interstate 25) I would want to put it in a box with a lot of lead when using it out in the field. Otherwise a bunch of goons in black with machine guns will stop your car. Some people who have had heart imaging done have been pulled over, it's mildly radioactive for a number of days. If their heart was giving them trouble they really had a heart attack after being pushed to the ground and machine guns held at their heads.
     
  20. rusty71

    rusty71 Member

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    Very interesting thread. Doctors are now telling us to get 15-20 minutes of direct sun per day to help with Vitamin D levels to prevent certain cancers. And of course every individual has different tolerances to radiation. Last year the local paper ran a story about a judge well in his 70's. Before law school this guy was famous for having been in the most above ground atom bomb tests in the 50's and early '60s! His reason for volunteering was "It was the closest army base to Las Vegas!". This guy has no ill health effects. The docs ought to study him top to bottom.
     
  21. 2F/2F

    2F/2F Member

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    Hell. The sun, other cosmic rays, and the various Earthborne types of decay radiation are downright unhealthy compared to that lens!

    As a nuke mechanic on subs, I got less exposure when submerged than I did as a civilian driving to work every day in Southern California and living in a 100-year-old house.

    Your average Joe or Josephine gets about 300mRem per year from various sources. I think the most exposure I ever got while aboard was not even 40mREM in a year, and this year included a reactor shutdown and a good deal of work in the Rx compartment itself. That is considered well within limits for the Navy, but still relatively high, due to the work in close proximity to the Rx itself. Most of our exposure is from betas that come from the decay of Co-60 that gets lodged in low points in the system or around junctions, pumps, valves, etc. That C-60 is created when the stable Co-59 is impacted by a particle ejected into the primary coolant from the fuel itself. The Co-59 gets into the coolant due to wear. (Valve seats, etc.) So, as you can see, it takes a lot to cause the primary source of exposure for us. Much more than it takes to just get hit directly by sunlight.
     
    Last edited by a moderator: Jul 27, 2008
  22. Marco B

    Marco B Member

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    Ole,

    Please note this was several years ago, but:

    That was exactly what I told him! Actually, my tool (a kriging spatial interpolator) showed that there was NO spatial relationship BETWEEN points with a 100% random nugget variance. This essentially means that the dataset (a very good one with over 10.000 measurements) may NOT be interpolated.

    However, that doesn't mean there isn't a spatial or better said statistical relationship between soil/rock types and Radon measurements. It just means that any two points close together have no spatial relationship. Realizing this, I figured this is simply caused by the fact that soil / bedrock types tend to vary over relatively short distances with one bedrock type being replaced completely by another, meaning that two houses separated by just 100 meter, might have totally different, and spatially unrelated, Radon levels.

    Such data may never be interpolated...

    I finally advised the guy to forget about a spatial interpolation, which simply is not allowed with such a dataset and 100% nugget variance (this was difficult for him to accept, like many other people, spatial interpolation of point measurements is often considered as the "holy grail" in GIS. "If I can interpolate it, it will be good...")

    I than advised him to try and statistically correlate soil / bedrock type with Radon levels in a normal statistical package, like SPSS. Simply by determining at what bedrock type, based on a geological map of Norway, the measurements were made, and to input that data in the statistical package together with the Radon levels. And maybe even include possible other variables as well, like building material of the houses or possible information about ventilation etc.

    If that would show a statistical relationship between soil / bedrock type and Radon levels, he could than reclassify his geological map of Norway based on low / high Radon risk or levels to get to a country wide map, which was what he was after...

    I don't know if he finally did this, (he sounded actually a little bit desperate at the point I told him he wasn't allowed to interpolate the fantastic dataset collected over years), but I hope so because with such a huge dataset, you can do some very interesting statistical analysis, just not interpolate it.
     
  23. Mark Layne

    Mark Layne Member

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    Talk about opening 'Pandora's Box'
     
  24. DMCarbo

    DMCarbo Member

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    Radioactive Ektar

    I actually just bought 2 Aero Ektars (Went a little bid happy and won both on ebay !) The Bokeh is amazing...opens up some really creative opportunities.

    I think you get more radiation sun bathing !

    Very Cool Glass !

    Dennis
     
  25. Marco B

    Marco B Member

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    Yes, they do seem to be capable of some remarkable images. The Pandora box is actually quite empty, as you can read from my original post and all the comments thereafter, about the only thing you probably better shouldn't do, is store your new lenses under your bed...
     
  26. Phillip P. Dimor

    Phillip P. Dimor Member

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    Great for portraits but I usually use mine one stop down from wide open, if not two. I know this probably negates the idea of using an aero-ektar in the first place but with the DOF being so shallow, it's very easy to end up with a fuzzy portrait with a sharp nose!