S-M-C and Super Takumar 50mm f1.4

[kuuan]

[estudleon]

+1

The best option for me too.

Rino.

[darosk]

Yes, seems most Takumar lens cap I acquire have trouble staying on lens. Sometime I dont even use the lens cap and just be careful.

[2contagious]

hi, I bought this lens without knowing about the radioactive element inside it. now I am wondering whether I should sell it again on eBay or keep it. the fact that I might be exposed to radiation while using it scares the heck out of me. does anybody know how much radiation the Super-Takumar 50 f1.4 really emits and what the "acceptable" amount of radiation in terms of health and safety is? I can't find anything that really helps on the internet it's usually either people making fun of it, people saying that it is not dangerous at all, and people saying the opposite... so I am confused. can anyone help me?

[luisalegria]

I an ME with a Nuclear Engineering minor. I have "some" connection with the industry.

1. It is not dangerous. It will not even register on a geiger counter. SOME radioactive lenses apparently will register, such as the famous Aero Ektar. Even so, its rather minor, and frankly anyones exposure to a lens would be very little. Its not going to be near you very much at all. Its not as if you will sleep with it under your pillow I think.

2. Natural background radiation varies so much around the earth, you would be surprised. Way, way more exposure range than any cumulative exposure from any lens, a factor of 4x from one place to another would not be unusual. If you are concerned, you should check whether your home is radioactive due to naturally occurring Radon gas (the biggest source) which depends on the local geology and the construction of your house, and b. the altitude at which you live; you want to be at sea-level to minimize it. And even with that, there has been no clear health effect found in differences in background radiation exposure. If anything, there is some support in the data for a BENEFIT from slightly higher background radiation (the hormesis effect).

3. Philosophically, I cannot understand why anyone would worry so much about very slight physical dangers. Life is for living, not preserving. We are all going to go, it doesn't matter all that much when it happens. Danger is good ! As Winston Churchill said, "There is nothing more exhilarating than to be shot at without result. " And thats a true thing.

So take out your Takumar lens, and use it for art with perhaps, if you like, the thrill of the knowledge of its radioactive parts.

[kuuan]

I am very much against nuclear power, but I have never worried even a bit about using the S-M-C Tak 1.4/50mm:

[estudleon]

I use my S-M-C 1,4 and not worry about nothing. I only enjoy the lens and the pics taken with it.

I read in a german forum that the konica 1,2/57 is so yellow 'cos is a radiactive lens too.

Wow.

Rino.

[2contagious]

I guess the fear mostly comes from not properly understanding radioactivity as well.. for example: when using it, I would be exposed to "that bit of radiation" it emits, but what about putting it somewhere.. will the radioactivity affect objects around it? as in... if I put it next to other lenses, will they be "contaminated" a bit and carry a bit of radioactivity? and will the inside of the camera be affected as well? or does the radioactivity stay in the lens ONLY and only affect objects/people while it is being used? in other words: does radioactivity leave traces or is it completely local?

[luisalegria]

The simple answer here is no.

The types of particles it emits are not the sorts that would make other objects radioactive. They can initiate some chemical reactions, such as that which turns the glass yellow.

The radioactive source is extremely weak, only capable of creating sufficient chemical reactions in its own glass matrix to turn it yellow after forty years - and most of the alpha and beta particles that do that job are blocked by the glass and metal of the lens itself.

It would only be potentially dangerous to a human if this Thorium-impregnated glass were to be somehow ingested, such that the alpha and beta particles were directly absorbed by cells in human organs. Perhaps also if a thorium-glass eyepice were to be held up to the eye, millimeters away, for hours at a time every day, it might have some effect.

You don't need to worry about this lens in any way at all.

Update - This summary is from Oak Ridge National Laboratories (well, their university extension), on Thorium optics and exposure calculations -

http://www.orau.org/ptp/collection/consumer%20products/cameralens.htm

They figure 0.7 millirem annually from normal use of a camera with a typical thorium lens, and up to 2 millirem for significant use, carrying it 30 days a year for 6 hours a day. I expect they are also making assumptions about the lens being carried close to the body.

NRC Occupational exposure annual limit is 5000mrem, and US average background radiation exposure is around 350mrem - so this exposure from thorium glass would be trivial.

[lwsy711]

Radioactivity is everywhere in our life, the smoke sensor, cosmic ray, x-ray.......I think the fear comes from the idea of radioactivity turns something into yellow that seems to be very bad sign. Most people have no idea how many particles(not include photon) have hit their body everyday.

[hinnerker]

Yes, its a boring discussion, cause everybody who payed attention on school, and do understand the table of elements knows, that there was no danger (if he dont use the lens as a lollypop).
Its an Alpha emitter, with a reach of some inches.. not more.

Boring

Cheers
Henry

[luisalegria]

You do also get gamma from Thorium decay.

[hinnerker]

You wont really discuss this.. or want you?

Dont do that with me.. i have to improve my technical english first.

Cheers
Henry

[luisalegria]

No, not really, just being pedantic.

Its not dangerous in any way.

[kuuan]

anyway, it is a fantastic lens, it 'shines'

[larsr]

I recently got an SMC Pentax-M 50/1.4 for free, and I've understood it's pretty much the same lens as SMC Tak 50/1.4. Does anyone have more on this? I'm going to sell it soon anyway, but I'm thinking about trading it 1:1 for a Tak..

[estudleon]

KUUAN

Your pics are fantastics. Here and in others places too.

I like your portraits very much.

You are one of who have decided to me to try the S-M-C- 1,4. Thanks.

Rino.

[kuuan]

[kuuan]

[Uzay]

Beautiful pics, mine is on the way

Edit:Finally i've received my S-M-C Takumar 50mm 1.4, do you know where can i find both caps for this lens?

[2contagious]

Hi,

what exactly is the difference between SMC Takumar 50mm f1.4 and the Super Takumar 50 f1.4? Is it true that the SMC version is not radioactive?

see you,
chris.

[kuuan]

there are actualy 3, Super Takumar, Super Multi Coated Takumar and SMC Takumar
the first two share the same all metal body but the Super Tak has simpler coating, the SMC has slightly different body sporting a rubberized focus ring and shares the coating of the S-M-C.
Early, maybe most Super Tak only have 6 aperture blades, S-M-C and SMC have 8
to my knowledge all three of them have radioactive glass

[2contagious]

What about the SMC Takumar 55/2.0? did it have a thorium piece as well?

[urmelchen]

[kuuan]

great photos taken with this lens:
http://www.flickriver.com/groups/takumar_50mm_f14/pool/interesting/

cheers,
kuuan