SMC-M 50mm 1.7: Thorium?

moorerice · 08-30-2014, 09:27 AM

Hi
I want to buy a Pentax SMC-M 50mm 1.7 lens, but I'm not sure whether or not it contains thorium glass elements (radioactive).
I know that the radiation of thorium glass elements in old lenses isn't particulary dangerous. It's just a thing that I want to know before I buy it.

Thanks

calculator01 · 08-30-2014, 10:48 AM

I'm sure someone else will chime in with a definite answer, but I am pretty sure the M's are not radioactive. I don't think any of the Pentax K-mount lenses are. However, I could be wrong.

moorerice · 08-30-2014, 11:02 AM

Originally posted by calculator01

I'm sure someone else will chime in with a definite answer, but I am pretty sure the M's are not radioactive. I don't think any of the Pentax K-mount lenses are. However, I could be wrong.

Thanks. That's what I thought too.

**boriscleto** · 08-30-2014, 11:33 AM - **1 Like**

Pentax switched to Lanthanum in 1975 with the K series.

moorerice · 08-30-2014, 11:49 AM

Originally posted by boriscleto

Pentax switched to Lanthanum in 1975 with the K series.

Thank you very much.

08-30-2014, 09:27 AM	#1
moorerice New Member Join Date: Aug 2014 Posts: 3	SMC-M 50mm 1.7: Thorium? Hi I want to buy a Pentax SMC-M 50mm 1.7 lens, but I'm not sure whether or not it contains thorium glass elements (radioactive). I know that the radiation of thorium glass elements in old lenses isn't particulary dangerous. It's just a thing that I want to know before I buy it. Thanks

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08-30-2014, 10:48 AM	#2
calculator01 Veteran Member Join Date: Nov 2010 Location: Edmonton, Alberta Photos: Albums Posts: 817	I'm sure someone else will chime in with a definite answer, but I am pretty sure the M's are not radioactive. I don't think any of the Pentax K-mount lenses are. However, I could be wrong.

08-30-2014, 11:02 AM	#3
moorerice New Member Join Date: Aug 2014 Posts: 3 Original Poster	Originally posted by calculator01 I'm sure someone else will chime in with a definite answer, but I am pretty sure the M's are not radioactive. I don't think any of the Pentax K-mount lenses are. However, I could be wrong. Thanks. That's what I thought too.

08-30-2014, 11:33 AM - 1 Like	#4
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,475	Pentax switched to Lanthanum in 1975 with the K series.

08-30-2014, 11:49 AM	#5
moorerice New Member Join Date: Aug 2014 Posts: 3 Original Poster	Originally posted by boriscleto Pentax switched to Lanthanum in 1975 with the K series. Thank you very much.

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