Radioaktiv Lenses

tm64 · 11-20-2018, 07:49 AM

Hello Pentax community,

Is the SMC Pentax-M 50mm F1.7 radioaktiv?

Anyone here have tested it ?

thx a lot

victormeldrew · 11-20-2018, 08:36 AM

This has been asked and answered hundreds of times. Please try a search.

stillshot2 · 11-20-2018, 08:54 AM

Maybe this post helps?:

SMC-M 50mm 1.7: Thorium? - PentaxForums.com

tm64 · 11-20-2018, 09:52 AM

Originally posted by stillshot2

Maybe this post helps?:

SMC-M 50mm 1.7: Thorium? - PentaxForums.com

thx a lot, sure i have read this
the question is "Anyone here have realy tested it ?"

reh321 · 11-20-2018, 12:02 PM

Originally posted by tm64

thx a lot, sure i have read this
the question is "Anyone here have realy tested it ?"

There is no reason to test it once we know that they no longer use radioactive materials

Originally posted by boriscleto

Pentax switched to Lanthanum in 1975 with the K series.

asking whether they've tested it is like asking whether they've tested carrots sold in your city for radioactivity {and what do you mean by "radioactive"; if you get sufficiently sensitive instruments, many many things will show a very little level of "radioactivity"}

tm64 · 11-20-2018, 12:15 PM

Originally posted by reh321

There is no reason to test it once we know that they no longer use radioactive materialsasking whether they've tested it is like asking whether they've tested carrots sold in your city for radioactivity {and what do you mean by "radioactive"; if you get sufficiently sensitive instruments, many many things will show a very little level of "radioactivity"}

thx a lot for your answer
Can you tell me your source where you found the info that they no longer use radioactive material in coating on this lens?
Is there any official report from pentax?

**jlstrawman** · 11-20-2018, 12:55 PM

Radioactive lenses | Camerapedia | FANDOM powered by Wikia

tm64 · 11-20-2018, 01:00 PM

Originally posted by jlstrawman

Radioactive lenses | Camerapedia | FANDOM powered by Wikia

i found this on google too

but SMC Pentax-M 50mm F1.7 is NOT on the "Lenses Tested non-Radioactive"
so this website proof anything?

Wasp · 11-20-2018, 01:55 PM - **2 Likes**

I have heard of some early Takumars being (very) mildly radioactive, but never of any SMC lenses. Even if there was any, the magical SMC would block it.

JohnX · 11-20-2018, 02:23 PM

OP. Why is it important? Just interest? Surely there's no way the level of radioactivity in a Pentax lens could cause any harm.

MarkJerling · 11-20-2018, 02:23 PM - **2 Likes**

Originally posted by tm64

thx a lot, sure i have read this
the question is "Anyone here have realy tested it ?"

The more pertinent question would be: Does it matter?

tm64 · 11-20-2018, 02:40 PM

Thx a lot for interrest and replys
The question is just if this lens is radioaktiv or not , i not want make the lens bad or people not to use it.

I thought maybe someone here in this big community have already tested it

If a Takumars lens fall down and shadder and u breath in the dust it can be dangerouse or is this wrong?

Ronald Oakes · 11-20-2018, 02:49 PM - **2 Likes**

That lens is radiologically toxic ! Better send all of them to me !
Do a search and read up on here. I had a bunch of takumars tested and then did the "freakout" thing and ditched a bunch of them. Were they harmful ? I never really determined that , but on a personal level Im a lot more comfortable with them gone.
It caused me a lot of stress and anxiety wondering and worrying , But then again I have had lots of cancers so any exposure to anything is cumulative.
For the normal person they are quite inane and harmless.

**yucatanPentax** · 11-20-2018, 02:59 PM - **1 Like**

The lens you are asking about was produced after thorium oxide was no longer used in lenses. Probably no one has tested it because Pentax no longer used any radioactive elements.

If you really want proof, I guess you could go to your local fire department HazMat unit and ask if they'll test the lens with one of their Geiger counters. Or buy one and do it yourself.

https://www.amazon.com/RADEX-RD1503-dosimeter-accuracy-radiation/dp/B005ZQ47...ger+counter%2C

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.

It's been said that if you held one of the thorium lenses to your chest for an hour, it might be equivalent to one modern day x-ray. That's pretty low, considering an x-ray is a fraction of a second, compared to an entire hour's exposure.

MarkJerling · 11-20-2018, 02:59 PM

Originally posted by tm64

Thx a lot for interrest and replys
The question is just if this lens is radioaktiv or not , i not want make the lens bad or people not to use it.

I thought maybe someone here in this big community have already tested it

If a Takumars lens fall down and shadder and u breath in the dust it can be dangerouse or is this wrong?

About as dangerous as eating a bunch of bananas.

Have a read of this thread: https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/354034-thr...ss-lenses.html

11-20-2018, 07:49 AM	#1
tm64 New Member Join Date: Nov 2018 Posts: 8	Radioaktiv Lenses Hello Pentax community, Is the SMC Pentax-M 50mm F1.7 radioaktiv? Anyone here have tested it ? thx a lot

11-20-2018, 02:59 PM - 1 Like	#14
yucatanPentax Loyal Site Supporter Join Date: Dec 2009 Location: Dallas / Yucatan Posts: 1,840	The lens you are asking about was produced after thorium oxide was no longer used in lenses. Probably no one has tested it because Pentax no longer used any radioactive elements. If you really want proof, I guess you could go to your local fire department HazMat unit and ask if they'll test the lens with one of their Geiger counters. Or buy one and do it yourself. https://www.amazon.com/RADEX-RD1503-dosimeter-accuracy-radiation/dp/B005ZQ47...ger+counter%2C 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. It's been said that if you held one of the thorium lenses to your chest for an hour, it might be equivalent to one modern day x-ray. That's pretty low, considering an x-ray is a fraction of a second, compared to an entire hour's exposure. Last edited by yucatanPentax; 11-20-2018 at 03:06 PM.

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11-20-2018, 08:36 AM	#2
victormeldrew Veteran Member Join Date: Jun 2015 Location: South West UK Photos: Albums Posts: 1,493	This has been asked and answered hundreds of times. Please try a search.

11-20-2018, 08:54 AM	#3
stillshot2 Pentaxian Join Date: Sep 2013 Location: Phoenix, AZ Photos: Albums Posts: 1,070	Maybe this post helps?: SMC-M 50mm 1.7: Thorium? - PentaxForums.com

11-20-2018, 09:52 AM	#4
tm64 New Member Join Date: Nov 2018 Posts: 8 Original Poster	Originally posted by stillshot2 Maybe this post helps?: SMC-M 50mm 1.7: Thorium? - PentaxForums.com thx a lot, sure i have read this the question is "Anyone here have realy tested it ?"

11-20-2018, 12:02 PM	#5
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,180	Originally posted by tm64 thx a lot, sure i have read this the question is "Anyone here have realy tested it ?" There is no reason to test it once we know that they no longer use radioactive materials Originally posted by boriscleto Pentax switched to Lanthanum in 1975 with the K series. asking whether they've tested it is like asking whether they've tested carrots sold in your city for radioactivity {and what do you mean by "radioactive"; if you get sufficiently sensitive instruments, many many things will show a very little level of "radioactivity"}

11-20-2018, 12:15 PM	#6
tm64 New Member Join Date: Nov 2018 Posts: 8 Original Poster	Originally posted by reh321 There is no reason to test it once we know that they no longer use radioactive materialsasking whether they've tested it is like asking whether they've tested carrots sold in your city for radioactivity {and what do you mean by "radioactive"; if you get sufficiently sensitive instruments, many many things will show a very little level of "radioactivity"} thx a lot for your answer Can you tell me your source where you found the info that they no longer use radioactive material in coating on this lens? Is there any official report from pentax?

11-20-2018, 12:55 PM	#7
jlstrawman Site Supporter Join Date: Feb 2010 Location: Midwest US Photos: Gallery Posts: 1,058	Radioactive lenses \| Camerapedia \| FANDOM powered by Wikia

11-20-2018, 01:00 PM	#8
tm64 New Member Join Date: Nov 2018 Posts: 8 Original Poster	Originally posted by jlstrawman Radioactive lenses \| Camerapedia \| FANDOM powered by Wikia i found this on google too but SMC Pentax-M 50mm F1.7 is NOT on the "Lenses Tested non-Radioactive" so this website proof anything?

11-20-2018, 01:55 PM - 2 Likes	#9
Wasp Pentaxian Join Date: Mar 2017 Location: Pretoria Photos: Gallery Posts: 4,661	I have heard of some early Takumars being (very) mildly radioactive, but never of any SMC lenses. Even if there was any, the magical SMC would block it.

11-20-2018, 02:23 PM	#10
JohnX Pentaxian Join Date: Jul 2009 Location: London Posts: 1,116	OP. Why is it important? Just interest? Surely there's no way the level of radioactivity in a Pentax lens could cause any harm.

11-20-2018, 02:23 PM - 2 Likes	#11
MarkJerling Moderator Site Supporter Join Date: May 2012 Location: Wairarapa, New Zealand Photos: Gallery \| Albums Posts: 20,406	Originally posted by tm64 thx a lot, sure i have read this the question is "Anyone here have realy tested it ?" The more pertinent question would be: Does it matter?

11-20-2018, 02:40 PM	#12
tm64 New Member Join Date: Nov 2018 Posts: 8 Original Poster	Thx a lot for interrest and replys The question is just if this lens is radioaktiv or not , i not want make the lens bad or people not to use it. I thought maybe someone here in this big community have already tested it If a Takumars lens fall down and shadder and u breath in the dust it can be dangerouse or is this wrong?

11-20-2018, 02:49 PM - 2 Likes	#13
Ronald Oakes Pentaxian Join Date: Jul 2017 Location: Virginia Posts: 1,582	That lens is radiologically toxic ! Better send all of them to me ! Do a search and read up on here. I had a bunch of takumars tested and then did the "freakout" thing and ditched a bunch of them. Were they harmful ? I never really determined that , but on a personal level Im a lot more comfortable with them gone. It caused me a lot of stress and anxiety wondering and worrying , But then again I have had lots of cancers so any exposure to anything is cumulative. For the normal person they are quite inane and harmless.

11-20-2018, 02:59 PM	#15
MarkJerling Moderator Site Supporter Join Date: May 2012 Location: Wairarapa, New Zealand Photos: Gallery \| Albums Posts: 20,406	Originally posted by tm64 Thx a lot for interrest and replys The question is just if this lens is radioaktiv or not , i not want make the lens bad or people not to use it. I thought maybe someone here in this big community have already tested it If a Takumars lens fall down and shadder and u breath in the dust it can be dangerouse or is this wrong? About as dangerous as eating a bunch of bananas. Have a read of this thread: https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/354034-thr...ss-lenses.html