Just posted this in the alt--image thread but I think it belongs here (more than there).
Found this:
Appears all metalgrip version where radioactive.
(serial Range XXX refers to XXX times 1000).
Version 1 (1968-1969) Serial# Range 200-257
58mm MC Rokkor-PG F/1.2 (Introduced on September 16th 1968)
Radioactive Coatings
Metal Focus Ring
Silver Aperture Ring Version 2 (1969-1973) Serial# Range 258-259
58mm MC Rokkor-PG F/1.2
Non-Radioactive Coatings
Rubber Focus Ring
Black Aperture Ring Version 3 (1973-1978) Serial# Range 271-277
58mm MC Rokkor-X (in orange) PG F/1.2 (Designated Rokkor-X only in the USA & Canada)
In the rest of the world it was labeled Rokkor (with white lettering)
It debuted in March 1973 (Other Rokkor-X lenses arrived earlier in 1972)
Improved Coatings from Version 2
WFrank,
this is good info.Thanks for your effort.My serial # is 258 but it still has the black metal focus ring.So i am still not sure if it has radioactive coatings or not.
-Jim
wfrank wrote:
Just posted this in the alt--image thread but I think it belongs here (more than there).
Found this:
Appears all metalgrip version where radioactive.
(serial Range XXX refers to XXX times 1000).
Version 1 (1968-1969) Serial# Range 200-257
58mm MC Rokkor-PG F/1.2 (Introduced on September 16th 1968)
Radioactive Coatings
Metal Focus Ring
Silver Aperture Ring Version 2 (1969-1973) Serial# Range 258-259
58mm MC Rokkor-PG F/1.2
Non-Radioactive Coatings
Rubber Focus Ring
Black Aperture Ring Version 3 (1973-1978) Serial# Range 271-277
58mm MC Rokkor-X (in orange) PG F/1.2 (Designated Rokkor-X only in the USA & Canada)
In the rest of the world it was labeled Rokkor (with white lettering)
It debuted in March 1973 (Other Rokkor-X lenses arrived earlier in 1972)
Improved Coatings from Version 2...Show more →
-I responded in the alt image thread but I suppose the conversation got moved over here.
Thank you very much for looking this up wfrank, but unfortunately I have to doubt it's accuracy. I am not worried about radiation poisoning, I am just pretty sure that neither of mine are thorium glass even though both are metal-gripped versions in the 250 range.
helimat wrote:
-I responded in the alt image thread but I suppose the conversation got moved over here.
Thank you very much for looking this up wfrank, but unfortunately I have to doubt it's accuracy. I am not worried about radiation poisoning, I am just pretty sure that neither of mine are thorium glass even though both are metal-gripped versions in the 250 range.
Yep, must be some error there - I think it was Jim S that also had an example contradicting the list.
Just received my lens, a metal beauty for sure. Definetly sharp-enough at F/1.2 the few shots I've taken in the total darkness that is in this part of the world now. Hope to do some real shooting this weekend. But there's a possible problem with mine, I just posted a thread here, please have a look and see if you (anyone here I mean) knows what it is. Thanks. https://www.fredmiranda.com/forum/topic/1069230
R.Young, no loose screws on mine. It's a Canon converted version and seem sturdy.
Propsep, Jim S, Gonzales - nice images and good inspiration for my 5D2 :-)
Helimat, why do you say you dont have a metal thorium version? As far as I know the yellowing thing (if one bother) can be taken away with UV light. And mine (which the seller pointed out to be "slightly yellow") doesnt look that yellow to me. It's purple, blueish, green and sometimes yellow depending on how i look into it and in what lighting. Occasionally it's even clear too :-)
helimat wrote:
-I responded in the alt image thread but I suppose the conversation got moved over here.
Thank you very much for looking this up wfrank, but unfortunately I have to doubt it's accuracy. I am not worried about radiation poisoning, I am just pretty sure that neither of mine are thorium glass even though both are metal-gripped versions in the 250 range.
another point against the accuracy of this is that as far as i know nobody has ever used radioactive coatings. it is the glass itself of one of the elements that is radioactive. if we're starting a survey, mine has a 256 serial number and is definitely radioactive.
edit: if your looking for yellowing don't look at the reflections, look at a white card through the lens.
sebboh wrote:
another point against the accuracy of this is that as far as i know nobody has ever used radioactive coatings. it is the glass itself of one of the elements that is radioactive. if we're starting a survey, mine has a 256 serial number and is definitely radioactive.
edit: if your looking for yellowing don't look at the reflections, look at a white card through the lens.
Funny you should mention it, I actually just tried comparing several lenses by using a white card... We must be on the same wavelength, pardon the pun. And what do you know, there might be a very slight yellowish tint to the light passing through it compared to a few of my Contax lenses. Both are mine are 256xxxx as well. So maybe mine are thorium? Interestingly, my 85/1.7 Rokkor has the same tint, is in the 250xxxx range, but I have to wonder whether they used thorium glass in those as well...
wfrank wrote:
Helimat, why do you say you dont have a metal thorium version? As far as I know the yellowing thing (if one bother) can be taken away with UV light. And mine (which the seller pointed out to be "slightly yellow") doesnt look that yellow to me. It's purple, blueish, green and sometimes yellow depending on how i look into it and in what lighting. Occasionally it's even clear too :-)
I had not noticed any yellow cast on any images, nor do they glow in the dark. This discussion has come up here several times over the years, and I seem to remember that the thorium glass were only used in the earliest point of production, so that with the lack of yellow cast led me to believe mine were in fact not radioactive. Maybe I am wrong...
I have a 256xxxx 58 1.2 and it definitely is radioactive. My images are always quite yellow using this lens, need to leave it out in the sun for a while to cure it.
Anyway, I am really quiet at work so today I did a full tear down of my rokkor to regrease and tighten it up as it had quite a bit of play in the barrel. Had a nightmare to be honest, took all day to get it back together, but I'm glad I did, I now know it inside out and could do the same job again in probably an hour. If anyone needs help doing this I would be happy to help but I have not taken photos for a tutorial or anything.
It's now as good as new apart from a slightly more dampened focus ring, I'm hoping this will free up a little after a bit of use. I used lithium grease which is all I had, maybe it is a little more vicious than the original grease.
For me using a white paper there is a yellowish tone comparing to e.g. EF 85/1.8. Funny, any chance that it is increasing contrast as with yellow glasses?
Now it's loaded. Hope to come back soon. Sry for the commercial look...
Thanks. Yes after having used NEX 5N for a couple of month this old but very capable giant feels inspiring. But what are you using right now doing your marvels?
Just to let you know, the mirror hits when above 5 meters focusing distance or so. But with LV you avoid it since it is a "mirror lock up mode". Just found that out after new noise sensations while trying it out. Otherwise I personally prefer the EG-S matte.
helimat wrote:
Funny you should mention it, I actually just tried comparing several lenses by using a white card... We must be on the same wavelength, pardon the pun. And what do you know, there might be a very slight yellowish tint to the light passing through it compared to a few of my Contax lenses. Both are mine are 256xxxx as well. So maybe mine are thorium? Interestingly, my 85/1.7 Rokkor has the same tint, is in the 250xxxx range, but I have to wonder whether they used thorium glass in those as well...
I had not noticed any yellow cast on any images, nor do they glow in the dark. This discussion has come up here several times over the years, and I seem to remember that the thorium glass were only used in the earliest point of production, so that with the lack of yellow cast led me to believe mine were in fact not radioactive. Maybe I am wrong... ...Show more →
i recall hearing that the 85/1.7 was another where they used thorium early on. it was never necessary, but it was a good way to get high refractive index.
with regard to yellow cast, if you shoot with auto white balance on you shouldn't notice that your pictures are yellow because the camera adjusts for it. it's only if you switch to a white balance preset that it becomes noticeable. if you take identical shots with an unthoriated lens and a thoriated lens with the same white balance the difference is obvious. for example here is a small version of a lens test i did a while ago where all shots were set to the same white balance value: http://farm6.staticflickr.com/5012/5412146377_d4480a05ef_z.jpg
the radioactive lens stands out pretty clearly. you can also see the differences in color balance used by different producers on closer inspection.
Wfrank, I currently use a 1ds2 as it was the cheapest option for full frame apart from the 5d1,which ironically I didn't like for the slow AF. Now I'm mainly mf so may as well get live view and a lighter body.
Sebboh, maybe you can get rid of the colour cast, but so far I'm finding it hard to do in Lightroom, white balance is one of the features I find hardest to use, unless it's already close I can never seem to get it right. I would also assume that there is a certain amount of degradation to the image, after all, we all use these expensive lenses to reduce our time in post, at least I do. I know processing can save images to a certain degree, but I am almost certain colours will be spoiled to some degree by the yellowing, even after correction in post.
Both are mine are 256xxxx as well. So maybe mine are thorium? 
Interestingly, my 85/1.7 Rokkor has the same tint, is in the 250xxxx range, but I have to wonder whether they used thorium glass in those as well...