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06-25-2013, 02:11 AM   #1
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Non Radioactive M42 Lenses for Spotmatic Family?

Hello,

I am new to Pentax. I am a fan of durable and small classic Nikons - the FM/FE family, as well as the F2 and F3. As I age, I gravitate more to robust classic cameras.

I have always wanted to explore the Spotmatic family and bought a nice Tak 50. It was beautiful and the focus ring was nice, but I discovered that it was radioactive. After some research, I decided that a radioactive lens is not for me, as I handle cameras and lenses for a considerable time in my hands (I make no claims to health issues from using a radioactive Tak - it was a personal decision only and this post is not intended to solicit a debate).

I still wish to explore the Spotmatics. Do I have options with quality non radioactive M42 Pentax or other M42 brands?

06-25-2013, 02:22 AM   #2
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Most sources agree there are only two thoriated Takumars. The 7-element 50/1.4 and the second version 35/2 (49mm filter). The original 8-element Super Takumar 50/1.4 does not have a Thoriated element and the first version 35/2 (67mm filter) shouldn't either.

Camerapedia makes claims about the 55mm and 85mm as well, but they are not as well documented (Unless you consider some guy holding up a cheap Dosimeter to a lens on YouTube documentation).

Radioactive lenses - Camerapedia
06-25-2013, 03:26 AM - 2 Likes   #3
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If you're really worried about that level of radiation, then you should avoid contact with the ground and drinking any fluids such as water.
06-25-2013, 06:45 AM   #4
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QuoteOriginally posted by ArticFox Quote
Hello,

I am new to Pentax. I am a fan of durable and small classic Nikons - the FM/FE family, as well as the F2 and F3. As I age, I gravitate more to robust classic cameras.

I have always wanted to explore the Spotmatic family and bought a nice Tak 50. It was beautiful and the focus ring was nice, but I discovered that it was radioactive. After some research, I decided that a radioactive lens is not for me, as I handle cameras and lenses for a considerable time in my hands (I make no claims to health issues from using a radioactive Tak - it was a personal decision only and this post is not intended to solicit a debate).

I still wish to explore the Spotmatics. Do I have options with quality non radioactive M42 Pentax or other M42 brands?
Brazil nuts are radioactive.

As is Grand Central Station in New York City.

Don't believe me? Look it up.

06-25-2013, 06:49 AM   #5
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Welcome to the Pentax Forums!

There is a lot of discussion regarding which vintage lenses have radioactive rare earth elements. It seems like the list expands whenever somebody who has access to a Geiger counter points it at their favorite lens. There is a recent group of postings on Flickr that added a dozen or so lenses from most major makers to the "hot" list including the S-M-C 55/1.8 at a bit more than half the count as the S-M-C 50/1.4.

Radioactive lenses -- group shot | Flickr - Photo Sharing!

I agree that there is no need to ignite a debate about whether there is a need for caution (mods may pull preceding non-helpful posts). Please don't feed the trolls and please don't be a troll or seek to insult a new forum member.


Steve

(For the record...currently owns two lenses on the list...wishes to have a couple more...)

Last edited by stevebrot; 06-25-2013 at 07:05 AM.
06-25-2013, 07:06 AM   #6
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Is time for you to seal yourself in a bubble... there are things out there that you use daily that are far more radioactive than the glass on your lens.

Oh and welcome to the forums .
Don't take everything too seriously, nobody is putting you down in any way .
06-25-2013, 07:07 AM   #7
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The radioactivity is very low. If you get a photo taken at the dentist or get a flight in an airplane you already get a higher dose.

I did the math once, it there are about as readioactive as 500 bananas.
I believe fish these days are also pretty radioactive, very curious how they compare.
06-25-2013, 07:24 AM   #8
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It's totally fine to handle them with your hands, your skin can handle minor radioactivity. Just don't put the glass right up to your eyes.

It also goes without saying not to tape the lens to your forehead and walk around with it 24/7

That being said, if you still feel uncomfortable with these lenses, you could always get the later made versions which lack the radioactive element.

06-25-2013, 07:37 AM   #9
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QuoteOriginally posted by Nagimaru Quote
That being said, if you still feel uncomfortable with these lenses, you could always get the later made versions which lack the radioactive element.
Except that the OP uses a Spotamatic (M42). In that mount, radioactive elements are more common than in the later K-mount glass. In the Pentax line, this would include both the S-M-C and SMC Takumars. A generalization may be made that thoriated glass is generally more common in faster lenses at the normal and wider focal lengths, so I would think that most 28mm and 35mm lenses at f/2.8 are probably pretty "cold". Ditto for 135mm at f/2.8.


Steve

Last edited by stevebrot; 06-25-2013 at 07:46 AM.
06-25-2013, 07:44 AM   #10
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Have you ever tried any Soviet lenses? I think you'd have fun with a Helios 44. I've read somewhere that it's the most-produced lens in history. Don't know if it's true or not, but there sure are a lot of them out there. They're worth about $30 shipped from wherever they are, usually in Russia or one of the former Soviet bloc countries. There are lots of different versions, but most have some sort of swirl in the out-of-focus areas. It's very unique. This effect is even more pronounce in the Helios 40, but that's a much more rare and expensive lens.
06-25-2013, 08:15 AM   #11
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QuoteOriginally posted by Nagimaru Quote
It also goes without saying not to tape the lens to your forehead and walk around with it 24/7
I can be wrong but with the strength radiowaves smartphones these days, wouldn't they be more damaging?
06-25-2013, 10:39 AM   #12
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QuoteOriginally posted by Anvh Quote
I can be wrong but with the strength radiowaves smartphones these days, wouldn't they be more damaging?
Apples and bananas


Steve
06-25-2013, 10:48 AM   #13
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QuoteOriginally posted by stevebrot Quote
Apples and bananas
Don't forget the granite countertops!
06-25-2013, 01:26 PM   #14
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"Radioactivity" also needs to be better defined to assess any hazards. Thorium oxide is primarily an alpha particle emitter, although a small amount of gamma is reported. The very low dose rates measured usually combine alpha and gamma. Alpha particles are blocked by as little as a sheet of paper, or the outer layer of skin, so only the minuscule amount of gamma would penetrate the body. As mentioned already, there are many common sources of more gamma radiation around us all the time.
There are more important things to worry about.
06-25-2013, 02:24 PM   #15
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Boriscleto, Stevebrot, scratchpaddy, and TomB_tx, - thank you for your sincere and interesting responses. Although it was not my intent, radioactivity in a lens was a good topic to test the personality of a forum. Some forums such as Photo.net, an Miranda are nice and few in between, so it will be interesting to see how Pentax Forums holds out over time.

The Helios 44 is mentioned in one of the best forum strings I have ever encountered on Miranda's "most magical lenses". I spent more than a month reviewing that string.

After you mention it, radioactive lenses do seem prominent in fast glass.

I do not have a Pentax yet, but I have my eyes on the Spotmatic and K family. Some time ago I tested the MX, but its size and balance was not there for me, but I should have tested a motor-drive with it. My guru repair guy for Leica (I don't intend to own a Leica) claims that the MX is internally the best built Pentax, without any other factors in consideration. I like mechanical cameras in concept, but, with my classic Nikons, I value the extended and less discrete shutter speed range that AE offers. Don't quote me, but I believe that the Pentax LX can AE for many minutes with changing light better than anyone, except for perhaps the OM2/4. I am also a big fan of a large, bright, and clear viewfinder, focus snap, and nice manual focus rings on the lens. I use a 10x compact Ziess binocular daily, so these things I like with cameras are probably associated with binocular use.
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