Home

Please support mflenses.com if you need any graphic related work order it from us, click on above banner to order!
SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

SMC Takumar 55 f1.8 radioctive?
Post new topic   Reply to topic
Home   Manual Focus Lenses
View previous topic :: View next topic  


PostPosted: Mon May 02, 2011 10:57 am    Post subject: SMC Takumar 55 f1.8 radioctive? Reply with quote
Problem is only of SMC Takumar 50mm 1.4 or also for SMC 55mm 1.8? It depends from SMC tratment? Normal versions are less radiocative? Thanks.


PostPosted: Mon May 02, 2011 1:57 pm    Post subject: Reply with quote
First. The takumar 1,8/55 is not a radioactive lens. A lot of copies are yellowed. Why? Balsam, perhaps.

Second. The S-M-C- and the SMC are less radioactive than the oldest S.T.


Good luck. Rino.


PostPosted: Mon May 02, 2011 4:05 pm    Post subject: Reply with quote
My Super-Multi-Coated Takumar 55mm f/1.8 and Super Takumar 55mm f/2 are both radioactive, though somewhat less so than the S-M-C 50mm f/1.4 (unsurprisingly as the faster lens has larger elements). The yellowing can be helped by UV exposure as well known.


PostPosted: Mon May 02, 2011 4:24 pm    Post subject: Reply with quote
The 55/1.8, not radioactive ?
http://www.youtube.com/watch?v=oL3D7FQTHXo


PostPosted: Mon May 02, 2011 10:17 pm    Post subject: Reply with quote
I didn't know the images, thanks for that.

But I don't understand what are them meaning. What are the parameters of the radiactive and not radioactive lenses?

In the pentax's forums the general concept is that the 1,8/55 isn't radioactive. But if it's not true, welcome the notice. It's new for me.

Anyways, thanks.

Rino.


PostPosted: Mon May 02, 2011 10:36 pm    Post subject: Reply with quote
estudleon wrote:

In the pentax's forums the general concept is that the 1,8/55 isn't radioactive. But if it's not true, welcome the notice. It's new for me.


Well, may be that some 55mm f/1.8 Takumars are not radioactive, but the one in the video linked above certainly is, as is the S-M-C one I have. It's quite simple to see when comparing the dosimeter reading (and counter clicking/beeping) for “background” to that read from the rear element of the lens.


PostPosted: Tue May 03, 2011 5:16 am    Post subject: Reply with quote
I completely diassembled a Super Takumar 55/1.8 and one of the lens was clearly radioactive : not as clear as the other Wink


PostPosted: Tue May 03, 2011 6:02 am    Post subject: Reply with quote
I've not seen a yellowed 55mm F1.8 SMC Tak so I'm surprised that they are radioactive. Also it would see that I have 3 radioactive lenses. Time to invest in a concrete storage case. Cool Laughing


PostPosted: Tue May 03, 2011 8:53 am    Post subject: Reply with quote
omg.... i never thought my lenses could be radiation poisoed.
but its evident...soviet equipment from the 80's? + cold war era? = radiation possiblility...

hmm i think on these videos they are not measuring gamma waves.
btw everything radiates, the whole world., but not with health endangering level.

btw if i die in cancer, i will never know what caused it (quit smoking on dec6) so i nevermind of the lens radiation..


PostPosted: Tue May 03, 2011 9:37 am    Post subject: Reply with quote
gorbesz wrote:
omg.... i never thought my lenses could be radiation poisoed.
but its evident...soviet equipment from the 80's? + cold war era? = radiation possiblility...


you may not know, radioactive glass was used because of optical properties, see e.g. http://camerapedia.wikia.com/wiki/Radioactive_lenses


PostPosted: Tue May 03, 2011 9:43 am    Post subject: Reply with quote
yup, dig myself into the topic. found out they used thorium for "light refraction", etc... these soviets Smile


PostPosted: Tue May 03, 2011 9:54 am    Post subject: Reply with quote
gorbesz wrote:
yup, dig myself into the topic. found out they used thorium for "light refraction", etc... these soviets Smile


another hint: Takumars were made in Japan by Asahi Optical Company, resp. Pentax, quite a few Kodak, also Canon, Minolta, Yashica lenses have radioactive glass, not sure if Russian manufacturers used radioactive glass


PostPosted: Tue May 03, 2011 10:08 am    Post subject: Re: SMC Takumar 55 f1.8 radioctive? Reply with quote
I tested the SMC Takumar 55/2 - he was radioactive.
About 80 micro-roentgen per hour.

SMC Takumar 55/2 and SMC Takumar 55/1.8 similar.


PostPosted: Tue May 03, 2011 11:29 am    Post subject: Re: SMC Takumar 55 f1.8 radioctive? Reply with quote
Kamerer wrote:
I tested the SMC Takumar 55/2 - he was radioactive.
About 80 micro-roentgen per hour.

SMC Takumar 55/2 and SMC Takumar 55/1.8 similar.


Wow, it`s pretty dirty!!


PostPosted: Tue May 03, 2011 12:37 pm    Post subject: Reply with quote
gorbesz wrote:

btw everything radiates, the whole world., but not with health endangering level.


The world kills everyone eventually. =)


PostPosted: Tue May 03, 2011 2:11 pm    Post subject: Reply with quote
WOW My normal lens 1,4/50 is a LD lens (like a fluorite one) !!!!!!!

I didn't know it. Thanks!!

Rino.


PostPosted: Tue May 03, 2011 2:39 pm    Post subject: Reply with quote
kuuan wrote:
gorbesz wrote:
yup, dig myself into the topic. found out they used thorium for "light refraction", etc... these soviets :)


another hint: Takumars were made in Japan by Asahi Optical Company, resp. Pentax, quite a few Kodak, also Canon, Minolta, Yashica lenses have radioactive glass, not sure if Russian manufacturers used radioactive glass


Does anyone know of a single mass-produced Soviet/Russian lens that is radioactive? Or German lens*, for that matter? Most of the radioactive ones seems to be Japanese, and then US (Kodak).


* Edit: Ah, actually I seem to recall that the 55mm f/1.4 Pancolar is radioactive, and maybe some P6 Biometar(?).


PostPosted: Tue May 03, 2011 3:35 pm    Post subject: Reply with quote
The yellowing is a secondary result of a radioactive element - if the radioactive one is glued to another element, it is the glue that yellows, as I understand it.

Thus if the 55 has a radioactive element, usually there isn't the telltale yellowing, and so people (myself included) assume it isn't radioactive.


PostPosted: Tue May 03, 2011 4:04 pm    Post subject: Reply with quote
Nesster wrote:

Thus if the 55 has a radioactive element, usually there isn't the telltale yellowing, and so people (myself included) assume it isn't radioactive.


Yeah, it's unfortunate that so many people use yellowing to “identify” radioactive lenses—not all radioactive lenses are prone to visible yellowing, and not all yellowed lenses are measurably radioactive.


PostPosted: Tue May 03, 2011 4:36 pm    Post subject: Reply with quote
Arkku wrote:
kuuan wrote:
gorbesz wrote:
yup, dig myself into the topic. found out they used thorium for "light refraction", etc... these soviets Smile


another hint: Takumars were made in Japan by Asahi Optical Company, resp. Pentax, quite a few Kodak, also Canon, Minolta, Yashica lenses have radioactive glass, not sure if Russian manufacturers used radioactive glass


Does anyone know of a single mass-produced Soviet/Russian lens that is radioactive? Or German lens*, for that matter? Most of the radioactive ones seems to be Japanese, and then US (Kodak).


* Edit: Ah, actually I seem to recall that the 55mm f/1.4 Pancolar is radioactive, and maybe some P6 Biometar(?).


Pancolars 1,8/50 are radioactives too, if we considered as radioactive lens the one in which the yellowish gone with UV treatment.
In the particular case of the pancolar 1,8/50, I left three of them under the sun light for some weeks and the yellow cast went.
And the oldeste the lens (pancolar zebra 2/50) the more yellowish it is.

The lastest with MC in white are not yellowish at all (only greenish) Laughing

Rino


PostPosted: Tue May 03, 2011 5:02 pm    Post subject: Reply with quote
estudleon wrote:

Pancolars 1,8/50 are radioactives too, if we considered as radioactive lens the one in which the yellowish gone with UV treatment.


We consider as radioactive lenses those that are actually radioactive as measured by a geiger counter (dosimeter, etc). My Pancolar 50mm f/1.8 is not radioactive.


PostPosted: Tue May 03, 2011 5:08 pm    Post subject: Reply with quote
Well, Arkku, thanks for put clear the things.

So, why the yellow single element of the yellowish lens is cleared when I put it under the sun (UV rays, no?).

This is a question that I never seen answered clearly.

Only one element, not cement yellowish, so what happen?

Rino.


PostPosted: Tue May 03, 2011 5:37 pm    Post subject: Reply with quote
estudleon wrote:
Well, Arkku, thanks for put clear the things.


To be fair, there are many different versions of the Pancolar 50mm f/1.8 so it is entirely possible that some version actually is radioactive even though mine isn't… But, my point is: it's not really possible to tell by yellowing, it must be measured.

estudleon wrote:

So, why the yellow single element of the yellowish lens is cleared when I put it under the sun (UV rays, no?).

This is a question that I never seen answered clearly.

Only one element, not cement yellowish, so what happen?


I don't actually know what exactly causes the yellowing, but it seems clear that whatever it is that turns yellow in or on the glass can be re-bleached by UV. However, UV does not “reverse” radioactive decay… Which is why some people claim that UV “can not” cure yellowing, even though it obviously can—therefore it seems obvious that the yellowing is not a direct consequence of materials changing due to their radioactive decay but rather something else that is “yellowed” by radioactivity and bleached by UV.

Now, remembering that we are constantly bombarded by radiation all around (cosmic radiation, radon gas, etc), even non-radioactive lenses will receive an extensive dose of radiation over the years. If they are not regularly used in sunlight (exposing them to UV), then it seems to me that they might just turn yellow from background radiation.

(That said, this is just speculation… The only thing I can say for sure is that I have had non-radioactive lenses that were yellow and could be bleached by UV, and I have radioactive lenses that are not particularly yellow.)


PostPosted: Tue May 03, 2011 5:55 pm    Post subject: Reply with quote
it may be due to glue that on its own tends to yellow. The UV bleaches the yellowing regardless of the agency of yellowing. Maybe?


PostPosted: Tue May 03, 2011 6:21 pm    Post subject: Reply with quote
Arkku wrote:
estudleon wrote:
Well, Arkku, thanks for put clear the things.


To be fair, there are many different versions of the Pancolar 50mm f/1.8 so it is entirely possible that some version actually is radioactive even though mine isn't… But, my point is: it's not really possible to tell by yellowing, it must be measured.

estudleon wrote:

So, why the yellow single element of the yellowish lens is cleared when I put it under the sun (UV rays, no?).

This is a question that I never seen answered clearly.

Only one element, not cement yellowish, so what happen?


I don't actually know what exactly causes the yellowing, but it seems clear that whatever it is that turns yellow in or on the glass can be re-bleached by UV. However, UV does not “reverse” radioactive decay… Which is why some people claim that UV “can not” cure yellowing, even though it obviously can—therefore it seems obvious that the yellowing is not a direct consequence of materials changing due to their radioactive decay but rather something else that is “yellowed” by radioactivity and bleached by UV.

Now, remembering that we are constantly bombarded by radiation all around (cosmic radiation, radon gas, etc), even non-radioactive lenses will receive an extensive dose of radiation over the years. If they are not regularly used in sunlight (exposing them to UV), then it seems to me that they might just turn yellow from background radiation.

(That said, this is just speculation… The only thing I can say for sure is that I have had non-radioactive lenses that were yellow and could be bleached by UV, and I have radioactive lenses that are not particularly yellow.)


Thanks Arkku.

All the information about that theme always is welcome.

Everything that we can add to our knowledge is a good thing. And more when the health can be involved.

Rino
Post new topic   Reply to topic
Home   Manual Focus Lenses
Goto page 1, 2  Next
Page 1 of 2