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radioactive lenses!?!


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#1 Bernhard Zitz

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Posted 10 March 2006 - 04:15 AM

I wondered why the glass of my Super Multi Coated Takumar 50mm F1.4 is so yellow, while the 28mm is perfectly clear. Some lenses were made of glass that includes traces of radioactive elements that decay over the years; which seems to be the reason some lenses get yellower and yellower.

Having a Geiger counter lying around, and to avoid doing something useful, I tested some lenses and adapters and found that some were radioactive.

The Takumar 50mm F1.4 is worst, it is also the most yellow

the super multi coated takumar 28mm is not radioactive nor yellow.

Angenieux 12-120mm F2.2 is a little radioactive as well a little yellow-green colored.

the Schneider 7-80mm F1.8 on the Nizo S800 is little radioactive. I never knew if the films turned out a little yellow because of the internal 85-Filter that could have suffered from age or if it was the lens....

The Schneider 7-56mm on the Nizo 2056 is very very little radioactive

Canon 7.5-60mm F1.4 on 814 is radioactive, color render seemed always correct

Canon 310XL, very little radioactive

Eumig mini3, very little radioactive

Switars 10mm F1.4, 25mm F1.4, 75mm F1.9, are very little radioactive, only the 25mm turns out a little blue, or maybe it's the others that are yellow?

All Minolta SLR lenses (MD) I tested are not radioactive, nor the Iscomorphot 8/1.5, the Kowa 16S, the Schneider Zoom and 10mm Cinegon on Leicina Special, Angeniuex 8-64mm F1.9 on ZM-4008II, Quarz S8 and DS8, Schneider Xenon 16mm(C-mount), Fujinon TV-Zoom Lens 14-84mm F1.6(C-mount), Lens on Chinon Super8, Agfa Moviezoom 6, Nikon 8x Super Zoom.

Overall the measured radioactivity is very low, the takumar 50mm which is worst, reaches only 1mR/h in peaks, those noted "very little" might might be within the error tolerance since my Geiger counter isn't very precise.

Maybe this test is completely stupid. I was just curious why some lenses get colored over the years...

knows anyone if this phenomenon affects color only, or has it other optical effects? are those lenses still as good as when they were new? (in terms of sharpness) Could a radioactive lens affect the film when someone lets the camera lying around for a while with the film in it, or letting the lens beside your unexposed films?

here a rather extreme method to resolve this problem: http://www.hermes.ne...ing/repair.html


cheers, Bernhard
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#2 Stephen Williams

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Posted 10 March 2006 - 04:31 AM

Hi,

The Cooke ser II 75mm is another prime example, still capable of beautiful images. In the past I placed some lenses on a sheet of Tri-x for a week in a lightproof box in a darkroom. The radioactive lenses did fog the film over time!

I guess that lens manufactures never intended lenses to have a useful life of 20-50 years!

Stephen

I wondered why the glass of my Super Multi Coated Takumar 50mm F1.4 is so yellow, while the 28mm is perfectly clear. Some lenses were made of glass that includes traces of radioactive elements that decay over the years; which seems to be the reason some lenses get yellower and yellower.

Having a Geiger counter lying around, and to avoid doing something useful, I tested some lenses and adapters and found that some were radioactive.

cheers, Bernhard


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#3 Dominik Muench

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Posted 10 March 2006 - 06:08 AM

Hi,

The Cooke ser II 75mm is another prime example, still capable of beautiful images. In the past I placed some lenses on a sheet of Tri-x for a week in a lightproof box in a darkroom. The radioactive lenses did fog the film over time!

I guess that lens manufactures never intended lenses to have a useful life of 20-50 years!

Stephen



uhh that would explain my hairloss...or maybe im just getting old.

imagine the possiblilities, "the new Carl Zeiss...Zoomlens And Eyelight in one, glows in the dark,your focus puller will love it" :)

do you have any information on the material they used ? was it some special sort fo quartz ?

Edited by Dmuench, 10 March 2006 - 06:09 AM.

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#4 Stephen Williams

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Posted 10 March 2006 - 07:52 AM

do you have any information on the material they used ? was it some special sort fo quartz ?


Hi,

Sorry I don't know exactly what was used.

Stephen
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#5 Dominik Muench

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Posted 10 March 2006 - 08:17 AM

no worries, i wonder if they did that on purpose or if it was just "contaminated" material they used for the lens manufacturing.
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#6 Dan Goulder

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Posted 10 March 2006 - 11:11 AM

do you have any information on the material they used ? was it some special sort fo quartz ?

The element called Thorium (Th) is responsible for the radioactive glass in some camera lenses. It was used to increase the refraction index of lenses from the 1930s through late 1980s. I'm sure that many of us would like to see a list of which specific lenses were manufactured with this element.
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#7 Dan Salzmann

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Posted 10 March 2006 - 12:02 PM

I've got the same thing on the eyepiece element of a Kinoptic finder for an ACLII. I'd love to replace it from Edmund Scientific Optics or elsewhere if I could find the specs on that exact part.
Seems like this type of was not only used for taking lenses.
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#8 Daniel Stigler

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Posted 10 March 2006 - 02:42 PM

imagine the possiblilities, "the new Carl Zeiss...Zoomlens And Eyelight in one, glows in the dark,your focus puller will love it" :)



Check this out: http://www.industrya...p?products_id=8

Number #1 on my wishlist... :D
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#9 Dominik Muench

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Posted 10 March 2006 - 02:56 PM

Check this out: http://www.industrya...p?products_id=8

Number #1 on my wishlist... :D



damn, there goes my technical achievement oscar :(
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#10 John Pytlak RIP

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Posted 10 March 2006 - 03:16 PM

Radioactive thorium can be found in a variety of items: xenon lamps, vacuum tubes, gas lantern mantles, some optical glasses, etc.
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#11 Tim Tyler

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Posted 10 March 2006 - 05:28 PM

Got back last night from a week at the Hanford Nuclear Reservation doing a segment for CBS 60 Minutes. Leslie Stahl introduced Hanford as 'The most contanimated place on the planet.' :(

Our 'guide' was telling me that they sometimes install video cameras to monitor the waste, but that the lenses go brown in a month or two. If left longer, he said, the electronics get fried too.
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#12 Dominik Muench

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Posted 11 March 2006 - 03:14 AM

Got back last night from a week at the Hanford Nuclear Reservation doing a segment for CBS 60 Minutes. Leslie Stahl introduced Hanford as 'The most contanimated place on the planet.' :(

Our 'guide' was telling me that they sometimes install video cameras to monitor the waste, but that the lenses go brown in a month or two. If left longer, he said, the electronics get fried too.




check out this story: http://www.kiddofspe...m/chapter1.html

amazing and scary pictures, id love to do a shoot there though.

for the first few years after the disaster aparently the trees in the surrounding forrest were glowing at night because they were contaminated so bad.
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