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09-19-2007, 05:05 PM   #1
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So who has a Radioactive Lens?

I came across this recently while researching a lens purchase. Tho, I seem to recall this from some other reading some time ago.

Much like leaded crystal glass, adding radioactive elements like thorium will increase the refractive index of the glass.

Anyway, some lenses of this vintage can have a yellow tint to the light going thru the the lens -- (not the reflection off the glass) This yellowness can be removed by laying the lens in the sun for a few days -- or heating it as one link claims.

Anyway, It looks like my Yashinon 55mm f/1.8 is radioactive, as will be my new Yashinon-DX f/1.4 that will be coming the mail soon -- can't wait to try that one out.

I haven't done much research into Pentax lenses, but some of those too are effected by this particularity of photography.

Here are some links for your curiosity if you're into this kinda thing.

Translated version of http://photo.6six6.de/Yashica_Objektiv_Radioaktivitaet.html

090.5

radioactive lenses pentax - Google Search

09-19-2007, 05:52 PM   #2
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If it doesn't bother Homer Simpson, then it doesn't bother me!

Would be interesting to see a list of affected lenses.
09-19-2007, 06:38 PM   #3
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I had a Tak M42 50mm f1.4 that suffered this issue. I wrapped it in tin foil and left the caps off. Just put it in a sunny window for a week one way then turned it around and left it for another week. The glass was clear after that. The tin foil keep the black body from overheating and allowing the focus ring lubricants from running on the aperture blades.

Last edited by Peter Zack; 09-19-2007 at 07:47 PM.
09-19-2007, 07:44 PM   #4
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I bow down at the alter of the Super-Takumar 50/1.4, in all of its radioactive, amber-hued magnificence. Goddamn I love that lens.

09-19-2007, 07:46 PM   #5
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Heh...I just noticed that you can just make out the yellow hue of the Tak 50/1.4 in my avatar at left.
09-19-2007, 10:18 PM   #6
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Finn... i think that Super-takumars are not Made with Thorium elements..i believe that Super-Multi-Coated takumar,SMC takumars and MAYBE ,not sure ,SMC pentax 50 mm 1.4 are radioactive lenses...but maybe the super takumar too...(?)If you like the Super -takumar,you should also try the Super-Multi-Coated Takumar 50mm 1.4..you would like it even better with the 8 blade diaphragm,and multi coated lenses..that lense is so sharp wide open,and free of color aberration it puts the 50mm 1.4 M to shame..i am now playing with a n"A" 50mm 1.4..lets see if image quality can compare with mighty S-m-c Tak....(although is fun to be able to use all shooting modes)
09-20-2007, 12:07 AM   #7
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Ah, my super-takumar is quite the radioactive lens.

I have this fantasy in my head of getting four of them, mounting them two by two, and going through airport security in the states with my nice twin tubes of radioactivity, and when questioned, just saying, oh, those are my camera lenses.

Course, thats just a fantasy. Im pretty sure I would get banned from air travel for that stunt.

But the yellow tint does come in handy to reduce the contrast on many of these high-contrast films, such as trusty Pan F+. Pulls out an extra stop or two of range on the film, and they print better as well. At least, thats my take on them.
09-20-2007, 03:27 AM   #8
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My Industar 61 50/2.8 has radioactive rear element in it. I believe the designers used Lanthanum in it. Something to do with where they source the silicon for the lenses.

The lens mount is 39mm x 26tpi and for the Leica Screw fit camera's. It's reported to be one the sharpest 50s around.

From what I have read the radioactivity levels are not much higher than normal background radioactivity level found in 99.9% of all everyday objects. I guess if you held it to your eye constantly for a fortnight it may cause you problems but in normal use the slightly higher levels are negligible.

09-20-2007, 11:20 AM   #9
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My Favorite Lens

Disassembly and Cleaning of the F1.4 50mm Super Takumar Lens

Thoriated Camera Lens (ca. 1970s)
09-20-2007, 11:38 AM   #10
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Here's really how to fix it (graphic violence)

Brian Ayling's photographic repair tips
09-20-2007, 11:47 AM   #11
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QuoteOriginally posted by jeffkrol Quote

All photos on this page are by Brian Ayling and Myles Harris-Ayling, using a Pentax Spotmatic II and SMC Takumar 1:2/55mm, exposed on Kodak Gold 100 colour print film.

Well, that's good to know.
09-20-2007, 06:15 PM   #12
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QuoteOriginally posted by jeffkrol Quote
Boy, I bet that guy wishes he had kept it and sold it. Have you seen how much S-M-C Takumars go for these days???

Makes me cringe...
09-20-2007, 06:55 PM   #13
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I just kept saying "NOooooooooooooo" everytime I see that page. How could he...
09-21-2007, 01:25 AM   #14
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Would a radioactive lens do anything to the sensor or the ICs? I don't know how much radiation these things put out.
09-21-2007, 10:45 AM   #15
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QuoteOriginally posted by Finn Quote
I bow down at the alter of the Super-Takumar 50/1.4, in all of its radioactive, amber-hued magnificence. Goddamn I love that lens.
And people think I'm crazy when I say that that lens has 'beautifully warm glass'...

But whatever you do, DON'T do anything to rid the glass of it's unique tint just yet! Wait until after the winter.. Certainly until after fall. The glass is going to make your foliage shots look out of this world!!

Mine is home right now sitting in complete darkness, cultivating it's unique bouquet of golden-amber hues dreaming of a day not too far in the near future when it can take ultra-sharp images of leaves. Yes, it lives for this. Leaves it says to me, LEAVES!
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