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12-06-2013, 01:57 PM   #16
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QuoteOriginally posted by elliott Quote
I've learned if trying to downsize lenses, you shouldn't accept trades in the Marketplace, I somehow ended up with more than I started with. I guess you could say I've had a great experience with the Marketplace here.


Thanks elliott.

After counting, I have over 100 lenses right now and have no time to play with them. I had no bad experience with other buyers. Instead I became friend with one of them and got invited to join in his thanksgiving gathering.

This buyer is from the same country where I am from. Shame on me``````


Last edited by xinanbei; 12-06-2013 at 02:18 PM.
12-06-2013, 01:58 PM   #17
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QuoteOriginally posted by VisualDarkness Quote
People are way to paranoid for some things like slight radioactiveness. The lens is nothing to worry about unless he plans to tape the lens with the rear element to one of his eyes and walk around with it. If it truly was that dangerous it would be forbidden to take on flights etc but it isn't. If he's still paranoid show him this forum.
Maybe my dear buyer is doing this right now.
12-06-2013, 02:10 PM   #18
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Almost every smoke detector in existence uses radioactive materials - which by necessity are exposed to the same air we breath. In my darkroom, I used an anti-static brush for cleaning negatives and slides that contained radioactive material. And there is a well-known dish pattern (Fiestaware from the 1930's) that used uranium to achieve its pretty orange color. Unless you are intending to eat the dish or another one of these radioactive devices, the danger is so minimal as to be non-existent. The reason I say 'eat', is the biggest danger is heavy metal poisoning, not radioactivity.

For what it is worth, I am a former emergency first responder for radioactive incidents - beta and gamma geigercounters and the whole bit. I kept a box of such radioactive scrapes and used them for demonstrations to school kids.
12-06-2013, 02:15 PM   #19
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QuoteOriginally posted by JimJohnson Quote

Almost every smoke detector in existence uses radioactive materials - which by necessity are exposed to the same air we breath. In my darkroom, I used an anti-static brush for cleaning negatives and slides that contained radioactive material. And there is a well-known dish pattern (Fiestaware from the 1930's) that used uranium to achieve its pretty orange color. Unless you are intending to eat the dish or another one of these radioactive devices, the danger is so minimal as to be non-existent. The reason I say 'eat', is the biggest danger is heavy metal poisoning, not radioactivity.

For what it is worth, I am a former emergency first responder for radioactive incidents - beta and gamma geigercounters and the whole bit. I kept a box of such radioactive scrapes and used them for demonstrations to school kids.
@JimJohnson

Thanks for your inputs. I started appreciating my stupid buyer. Now I have a chance to learn more knowledge. After calming down, now I think maybe he just doesn't like it and want an excuse to return. I am happy now to hear a lot of new things from all of you. I deeply appreciate all the comments.

12-06-2013, 02:18 PM   #20
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QuoteOriginally posted by stevebrot Quote
No, the radioactive glass (not the coating) is a well-documented design characteristic of the lens



No...see above



Not surprising...see above.


Many lenses made through much of the mid-20th century have elements made with thoriated glass. The rare earth element Thorium was added to fine-tune the refractive index of the glass. The radiation was a side-effect. The most notorious were lenses on various Kodak products though a comprehensive list includes lenses from most major manufacturers.

There are a number of Web articles that attempt to quantify the risk, but as noted above, the dosage from even regular use is pretty slight with intensity falling off by the square of the distance. To put it in terms that a photographer would understand...it is not enough to fog film.

As far as your purchaser is concerned, if you have additional conversation you might want to make the following points:
  • The price of the lens was very competitive and represents reasonable market value for similar items sold elsewhere
  • Retail outlets with similar product post no warning (use KEH as an example)
  • If the buyer is dissatisfied with the lens, he/she is welcome at any time to resell the lens with a warning to potential buyers regarding the radioactivity
  • There is no moral, ethical, or legal rational or precedent for you to be required to accept a return


Steve

(Has a couple of lenses on the shelf that are reputed to be radioactive...does not carry such in pants pocket...)
Steve, I looked back of your comment after calming down (kind of). I really adore your way of explaining. It is so rational. I have a lot to learn in my life I believe. Thanks again.
12-06-2013, 02:40 PM - 1 Like   #21
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QuoteOriginally posted by xinanbei Quote
Steve, I looked back of your comment after calming down (kind of). I really adore your way of explaining. It is so rational. I have a lot to learn in my life I believe. Thanks again.


Why thanks!


Steve

(...rational? Me?)
12-06-2013, 03:24 PM   #22
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QuoteOriginally posted by stevebrot Quote


Why thanks!


Steve

(...rational? Me?)

The appreciation comes from your words of explanation.
Ratioanal```en``````if it is a compliment, then yes```
12-06-2013, 03:57 PM   #23
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In a few decades, we Pentax shooters will be in high demand as professional photographers as we'll all have extra arms and eyes to shoot photos with, and also no children distracting us from our craft as we'll all be sterile.

12-06-2013, 04:05 PM   #24
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QuoteOriginally posted by northofpolaris Quote
In a few decades, we Pentax shooters will be in high demand as professional photographers as we'll all have extra arms and eyes to shoot photos with, and also no children distracting us from our craft as we'll all be sterile.
This is a good one. Overall we pentaxian rocks
12-06-2013, 04:08 PM   #25
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Maybe email him a link to this thread
***Joking*** (mostly).
Might educate him on the lens...and a few other things...
Cheers
Dean
12-06-2013, 07:08 PM   #26
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I don't understand the buyer's point because this was a characteristic of the lens when it was designed and sold as new. The buyer is intentionally choosing an older model lens, with whatever good and bad characteristics accompany that product. It would be like buying a car from the 1950s and claiming it was defective because it didn't come equipped with seat belts.
12-06-2013, 11:43 PM   #27
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Look at it this way: the radioactivity danger is from the decay of the radioactive nucleus, at which time it changes into something else.

In the optical glass the thorium mix was a low dispersion glass (so all colours pass through the same path to avoid chromatic aberations). If the thorium half life were short enough to make the radiation dangerous there would be too much decay of the thorium that the glass would no longer have the intended optical properties and the lens woudl be usefulss. But ince the half life is of the order of 250,000 years the thorium is stable enough to be useful in the lens AND of such low radioactivity as to be not a problem.

The only reason this glass is not used now is the OH&S risk to workers in the grinding room where dust could be airborne and breathed in leading to accummulation of possible radioactive and possible toxicity injuries.

But if the buyer does not want to keep a lens you sold at half (or less) of market value, give a refund and sell again to soemone who will pay you a fair market price becaus ethey iunderstand what they are buying. That would be your fastest 100% investment return.
12-07-2013, 07:42 AM   #28
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QuoteOriginally posted by tim60 Quote
Look at it this way: the radioactivity danger is from the decay of the radioactive nucleus, at which time it changes into something else.

In the optical glass the thorium mix was a low dispersion glass (so all colours pass through the same path to avoid chromatic aberations). If the thorium half life were short enough to make the radiation dangerous there would be too much decay of the thorium that the glass would no longer have the intended optical properties and the lens woudl be usefulss. But ince the half life is of the order of 250,000 years the thorium is stable enough to be useful in the lens AND of such low radioactivity as to be not a problem.

The only reason this glass is not used now is the OH&S risk to workers in the grinding room where dust could be airborne and breathed in leading to accummulation of possible radioactive and possible toxicity injuries.

But if the buyer does not want to keep a lens you sold at half (or less) of market value, give a refund and sell again to soemone who will pay you a fair market price becaus ethey iunderstand what they are buying. That would be your fastest 100% investment return.
Thanks for the detailed explanation. The buyer just live in his own world. He should have appreciated the price I sold and the time I spent on teaching him. Instead he is arrogant and make me look like a bad person.

I would say this is a good lesson. I wouldn't treat some one like him in this nice way anymore.
12-07-2013, 07:46 AM   #29
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QuoteOriginally posted by Dean Bradshaw Quote
Maybe email him a link to this thread
***Joking*** (mostly).
Might educate him on the lens...and a few other things...
Cheers
Dean
I did. he said it not worthy to do this, and in the end left some dirty words in my webchat.

Really laughable
12-07-2013, 07:49 AM   #30
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QuoteOriginally posted by tibbitts Quote
I don't understand the buyer's point because this was a characteristic of the lens when it was designed and sold as new. The buyer is intentionally choosing an older model lens, with whatever good and bad characteristics accompany that product. It would be like buying a car from the 1950s and claiming it was defective because it didn't come equipped with seat belts.
Nobody in my office understand him either. Whatever I explained, he still keep on calling. I finally yelled back and ask him stoping calling with last warning of calling 911

I would say he is a spoiled boy, thinking I am his father.
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