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11-20-2018, 03:30 PM   #16
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Here are results of one person's tests. Your lens is not on the list, but some of the other information may be interesting/helpful.

Radioactive Pentax Takumar lenses.

11-20-2018, 05:33 PM   #17
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QuoteOriginally posted by jlstrawman Quote
Radioactive lenses | Camerapedia | FANDOM powered by Wikia
I noticed the Pentax K 35mm f2 isn't on that list, but the Takulmar 35mm f2's are. I thought the K series one was radioactive?
11-20-2018, 06:51 PM - 1 Like   #18
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I have the M 50mm f/1.7 and am now disappointed it hasn't turned my other lenses into mutants. It doesn't even glow in the dark.
11-21-2018, 01:59 AM   #19
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I now find myself wondering if my Takumar 35mm f/2.3 poses a threat to my safety. I haven't seen it on any of the lists, but it might just be that nobody has tested one yet. It is said to be rare, after all.

Luckily for me, I don't use it very much. That is actually a bad thing, because it is an amazing lens. At least now I have an excuse for my laziness.

11-21-2018, 03:10 AM - 2 Likes   #20
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QuoteOriginally posted by Wasp Quote
I now find myself wondering if my Takumar 35mm f/2.3 poses a threat to my safety.
Yes, very dangerous. Almost as bad for your health as Jhb CBD.
If you send it to me I'll dispose of it safely.
11-21-2018, 03:14 AM   #21
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Today i talked to a nuklear Professor in my german high school and he confirmed if the lens shadders and u breath in the dust there is a high risk of get cancer spezial if u are in young age.
He also told me there are free apps in Android where everyone can detect if the lens is radioaktiv it works with the camera as detector.

I also called Pentax by phone but they did not know anything about SMC Pentax-M 50mm F1.7
11-21-2018, 03:36 AM   #22
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QuoteOriginally posted by tm64 Quote
Today i talked to a nuklear Professor in my german high school and he confirmed if the lens shadders and u breath in the dust there is a high risk of get cancer spezial if u are in young age.
He also told me there are free apps in Android where everyone can detect if the lens is radioaktiv it works with the camera as detector.

I also called Pentax by phone but they did not know anything about SMC Pentax-M 50mm F1.7
Please understand that, for you to come to harm from a thorium lens element, you'd have to grind the whole thing up and eat it. And even then, the radiation you'll receive will be minisculely small compared to many other naturally occurring things in nature.

In addition, not every lens element in a lens assembly used thoriated glass. As result, only if the thoriated element was the front or rear element in a lens assembly, and that element broke, would you have any risk. If one of the other lens elements broke, you would obviously have no risk at all.

Here's a scientific study that explains how small the level of radiation from an average thoriated lens is: http://www.diva-portal.org/smash/get/diva2:652338/FULLTEXT01.pdf

11-21-2018, 08:14 AM - 1 Like   #23
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QuoteOriginally posted by tm64 Quote
Today i talked to a nuklear Professor in my german high school and he confirmed if the lens shadders and u breath in the dust there is a high risk of get cancer spezial if u are in young age.
He also told me there are free apps in Android where everyone can detect if the lens is radioaktiv it works with the camera as detector.
The couple of times I’ve dropped lenses such that they broke, they have generally not shattered into dust that would be a breathing hazard. The glass, even though broken, was restrained by the body of the lens and the small amounts of dust were generally not airborne and were easy to pick up with a damp cloth.

I’d really like to know how an app is going to work as a radiation detector.
When you say the camera is the detector, I assume you mean the Android device camera, not the one the lens is on...

One reason I’m curious is that in my (now several year-old) experiences with Android, the diversity of camera suppliers made even an optical light meter challenging to develop across all Android devices, so I’d like to know how that was solved for radiation.

-Eric
11-21-2018, 08:17 AM - 1 Like   #24
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QuoteOriginally posted by tm64 Quote
if the lens shadders and u breath in the dust there is a high risk of get cancer
If you breathe in glass dust (radioactive or not) you have much worse problems to worry about.
11-21-2018, 08:30 AM   #25
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Hi Eric ,

i aso was very sceptical that an app can detect radiation, but after reading some test in google it seems realy working.
Yes the Android device camera detects it.

For me this was also new, i never thought thats even possible.

If you want know more about it u can read this article below or just download the app in appstore and gife it a try

Your Smartphone Can Measure Your Radiation Exposure
Government researchers have developed an app that turns an ordinary smartphone into a radiation detector by using the built in camera to detect gamma rays

Your Smartphone Can Measure Your Radiation Exposure








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11-21-2018, 08:47 AM   #26
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QuoteOriginally posted by yucatanPentax Quote
You have to remember that even the actually "radioactive" lenses were mounted on film cameras, in very close proximity to film for days or even months at a time. Severe radiation would have fogged the film. So, even the known thorium lenses had very low levels. So low that they didn't fog the camera's film.
Yes, there is way too much worry here over this issue. If film didn't notice that a lens is radioactive, then not likely we will

QuoteOriginally posted by victormeldrew Quote
If you breathe in glass dust (radioactive or not) you have much worse problems to worry about.
Like being cut by the glass.
11-21-2018, 08:54 AM   #27
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QuoteOriginally posted by stillshot2 Quote
I noticed the Pentax K 35mm f2 isn't on that list, but the Takulmar 35mm f2's are. I thought the K series one was radioactive?
No, the "radioactive glass" was used in making some Takumars.
11-21-2018, 09:18 AM   #28
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QuoteOriginally posted by reh321 Quote
No, the "radioactive glass" was used in making some Takumars.
I uploaded the two photos below with absolutely no processing - they are JPEGs straight out of my K-30.

The first was taken with my then-new-to-me "radioactive" Takumar 35mm (*). The second was with taken with my modern DA 18-135mm, The thing you will notice in comparing them is that the "radioactive" lens is tinted yellow, which is what the "radioactive" lenses are famous for; I left the lens on our deck for a few hours, and the yellow went away. I have never heard of that kind of issue with K, M, or later lenses, a good sign of no "radioactivity".


(*) the guy who sold it to me used USPS; their detectors were not set off by the lens, so it must emit very little radiation,
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11-21-2018, 09:42 AM   #29
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QuoteOriginally posted by reh321 Quote
No, the "radioactive glass" was used in making some Takumars.

Some SMC K lenses were also radioactive, probably a batch dependent thing.

Not that I'd worry about it anyways.
11-21-2018, 09:54 AM   #30
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@reh321

very interesting pics thx for showing us
if u put the "yellow" lens under UV-Light (or sunlight) for some days it will fix the problem for most lenses

---------- Post added 11-21-18 at 10:02 AM ----------

@ZombieArmy

i also have seen this video , can you tell me if this is a M lens from 1977 (SMC Pentax-M 50mm F1.4)
couse i have read in 1975 they changed using Thorium to Lanthanoxid
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