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03-30-2011, 12:16 PM   #31
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QuoteOriginally posted by boriscleto Quote
You do realize that only the 50 1.4 and 35 2 have Thorium dioxide elements right? None of the other Super, S-M-C, or SMC-Taks turn yellow. But if you want to be ignorant, more Taks for the rest of us.
Yes, I know that. An old watch with fluorescent hands and numerals probably put out more radiation than a thoriated lens.

03-31-2011, 07:58 PM   #32
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DANGER WILL Iivan, DANGER, DANGER

QuoteOriginally posted by Iivan Quote
Hi!
I just bought a beautiful Asahi Pentax Spotmatic with a Super Takumar lens (55/1,8). The camera shop said that these lenses are treated with Thorium and are somewhat radioactive. Does anybody know should this be a concern for your health?
best regards
Iivan
Without lens cover lens will burn hole in your bag. Best to send all super taks to me for proper care and disposal.
-Homer "Lead Brain" Simpson.
04-01-2011, 07:53 AM   #33
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QuoteOriginally posted by lithos Quote
I'm not trying that with any of the damn spiders around here.
A radioactive funnel-web aught to turn you into one helluva spiderman. Or at least a radioactive zombie.
04-01-2011, 07:55 AM   #34
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QuoteOriginally posted by violini Quote
After reading these posts, I automatically associate this brand name with "super dangerous", "redundant". When I pore over the market listings, I skip over Super Takumar.
Good. That helps keep the prices under control. Ironically, when I was at ORNL (aka X10), we used a coleman lantern mantel to calibrate our Geiger Counters.

04-01-2011, 08:38 PM   #35
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QuoteOriginally posted by Blue Quote
we used a coleman lantern mantel to calibrate our Geiger Counters
...another commonly available thoriated product!
04-02-2011, 08:29 AM   #36
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QuoteOriginally posted by EyeSpy Quote
Without lens cover lens will burn hole in your bag. Best to send all super taks to me for proper care and disposal.
-Homer "Lead Brain" Simpson.
This sounds like miniature "China Syndrome".
04-03-2011, 02:53 AM   #37
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Yes, thoriated lenses are dangerous, especially when eaten. But bananas are more radioactive than are thoriated lenses. No more banana shakes for YOU, mutant! And don't move to Denver.

04-03-2011, 04:15 AM   #38
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Look here:

http://www.orau.org/ptp/collection/consumer%20products/cameralens.htm

Chris
04-03-2011, 04:47 AM   #39
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This is just plain redikulus..

Tsk, tsk
methinks:

radioactive lens?

dosimeters are made of what exactly?

What is in the back of every operational 35mm camera?


Come on!
04-03-2011, 07:01 AM   #40
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QuoteOriginally posted by CRM-114 Quote
Tsk, tsk
methinks:

radioactive lens?
Yes, radioactive.

QuoteQuote:
dosimeters are made of what exactly?
A strip of x-ray film

QuoteQuote:
What is in the back of every operational 35mm camera?
Film, of course! Unless the camera is a shelf queen. And what protects the film? A couple pieces of glass and a fabric or metal shutter. Thanks for reminding everyone. The lens elements are radioactive and may even set off detectors at airports and elsewhere, but the health risks are very low due to the low energy of the radiation and the poor penetration.


Steve
08-13-2011, 09:37 PM   #41
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Although I am no nuclear scientists, I saw a video on Youtube (not sure I believe all I see anyway) in which they measure radiation from the SMC Takumar 50mm f1.4 (the strongest of all in radioativity), and it does emits. However, no ALPHA particles were measured, only BETA and GAMMA. What does it mean?
08-14-2011, 06:58 AM   #42
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QuoteOriginally posted by Pepe Guitarra Quote
Although I am no nuclear scientists, I saw a video on Youtube (not sure I believe all I see anyway) in which they measure radiation from the SMC Takumar 50mm f1.4 (the strongest of all in radioativity), and it does emits. However, no ALPHA particles were measured, only BETA and GAMMA. What does it mean?
PM me and I will send you the address of a special facility that has proper storage facilities for such lenses. Just in case you should also send me . . . err I mean the Facility your 85mm Taks of all vintage just in case.
08-14-2011, 01:19 PM   #43
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QuoteOriginally posted by Pepe Guitarra Quote
... However, no ALPHA particles were measured, only BETA and GAMMA. What does it mean?
The nuclei that are prodcued as a result of the alpha decay of thorium are themselves radioactive, they decay further in a number of steps to a stable isotope of lead. Some of the steps in the decay chain produce beta particles.

Still, because the half-life of thorium is very long (= rate of decay low) the resulting activity is low.
08-14-2011, 03:11 PM   #44
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QuoteOriginally posted by Blue Quote
PM me and I will send you the address of a special facility that has proper storage facilities for such lenses. Just in case you should also send me . . . err I mean the Facility your 85mm Taks of all vintage just in case.
I will do that. I need to dispose off about 7 Taks. Wait for my PM (sitting..., so you will not get tired of waiting )
08-16-2011, 11:37 AM   #45
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QuoteOriginally posted by violini Quote
After reading these posts, I automatically associate this brand name with "super dangerous", "redundant". When I pore over the market listings, I skip over Super Takumar.
A very wise move. Pentax lenses in general are hazardous. After only 36 years of exposure to them, my hair has turned gray and started to fall out.

John
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