Emanuel Posted July 17, 2016 Share Posted July 17, 2016 Apologies, that was my son typing, two of us use this account. Tweak Senior. xe-xe ;-) Quote Link to comment Share on other sites More sharing options...
Timotheus Posted July 17, 2016 Share Posted July 17, 2016 @tweak Note that we're talking about a 2014 post here. It's factual content is correct. That was all. Quote Link to comment Share on other sites More sharing options...
Emanuel Posted July 17, 2016 Share Posted July 17, 2016 3 minutes ago, Emanuel said: xe-xe ;-) Note that's LOL in Russian, not arabic either :-) Quote Link to comment Share on other sites More sharing options...
tweak Posted July 17, 2016 Share Posted July 17, 2016 What factual content? @Timotheus Quote Link to comment Share on other sites More sharing options...
fuzzynormal Posted July 18, 2016 Share Posted July 18, 2016 Is it possible for the radiation of a old lens to resurrect a zombie thread? Chrad, enny and mercer 3 Quote Link to comment Share on other sites More sharing options...
IronFilm Posted July 18, 2016 Share Posted July 18, 2016 Of course, radiation fits zombies like a glove. Zach Goodwin 1 Quote Link to comment Share on other sites More sharing options...
rwx Posted October 10, 2016 Share Posted October 10, 2016 OK for all you knowledgable people and know it all's and others who work in radiology and others that think they know it all, take a look at this. Tuck it under your bed, wrap it in tinfoil. put it in a box? P.S The cornea of your eye is extra sensitive to radiation on this level, forget what you recieve having an X-ray or a flight to Bangkok. Cinegain and Nikkor 2 Quote Link to comment Share on other sites More sharing options...
fuzzynormal Posted October 10, 2016 Share Posted October 10, 2016 2 hours ago, rwx said: Tuck it under your bed, wrap it in tinfoil. put it in a box I'm not taking the tinfoil off my head for anything. mercer, Nikkor, leslie and 3 others 5 1 Quote Link to comment Share on other sites More sharing options...
gh2sound Posted October 11, 2016 Share Posted October 11, 2016 The half life of this thread is long lol Quote Link to comment Share on other sites More sharing options...
Ivanhurba Posted October 11, 2016 Share Posted October 11, 2016 16 minutes ago, gh2sound said: The half life of this thread is long lol As long as a thorium particle radioactive decay :D Quote Link to comment Share on other sites More sharing options...
Cinegain Posted October 11, 2016 Share Posted October 11, 2016 Don't know what it is with these magical radioactive lenses. But the images do have a certain glow to 'em. leslie and Ivanhurba 1 1 Quote Link to comment Share on other sites More sharing options...
Kisaha Posted October 11, 2016 Share Posted October 11, 2016 I still use my Pentaxes, I just put them on a closet, instead of under my bed that stayed for 15 years! Quote Link to comment Share on other sites More sharing options...
Davey Posted October 11, 2016 Share Posted October 11, 2016 Ah, that will explain the green tint on all my Panasonic videos. Blue Fox 1 Quote Link to comment Share on other sites More sharing options...
Cinegain Posted October 11, 2016 Share Posted October 11, 2016 It's the resolution I suppose. We paint it red to fit right in! Quote Link to comment Share on other sites More sharing options...
Ivanhurba Posted October 12, 2016 Share Posted October 12, 2016 4 hours ago, Cinegain said: It's the resolution I suppose. We paint it red to fit right in! Gotta say I love this song and Daddario is out of this world, radioactive or not. Quote Link to comment Share on other sites More sharing options...
jgharding Posted October 12, 2016 Share Posted October 12, 2016 Half Life 3 confirmed... Nikkor 1 Quote Link to comment Share on other sites More sharing options...
Super Members Mattias Burling Posted October 12, 2016 Super Members Share Posted October 12, 2016 Im not a radiologist like Saadawi but I did some tests a while back. Kisaha, tweak and Cinegain 3 Quote Link to comment Share on other sites More sharing options...
tweak Posted October 12, 2016 Share Posted October 12, 2016 On 26 April 2014 at 6:54 PM, Ebrahim Saadawi said: Funny thing is I've been a physician for 40 years, with a PhD in Radiology for about 30, so I know a thing or two about radioactivity, and the extent of danger on us... hahahahaha funny indeed. The graph made me feel better @Mattias Burling. Mattias Burling 1 Quote Link to comment Share on other sites More sharing options...
unclean Posted December 3, 2019 Share Posted December 3, 2019 Hello Folks, Just thought I'd spice up the talk and point out that although Thorium is only an alpha emitter, its "daughter" products are beta emitters, which require a bit more shielding than paper. So, when 232 Thorium decays, releases an alpha, and becomes 228 Radium (HL 5.7 years), which throws off an electron (-beta particle) to 228 Actinium. That lasts just over 6 hours and throws another -beta particle to a lighter version Thorium--228 Thorium (HL 1.9 yr). Next, you loose another alpha and create 224 Radium in 3.5 days, which you create something a bit nasty, 220 Radon (HL 55 seconds) then another alpha particle and 216 Polonium (HL .14 sec). Losing another alpha, you come to 212 Lead (HL 10.6 hr). Throwing another -b particle, you come to 212 Bismuth (HL 60 min), where the decay takes two different paths. 64% of the time--it throws a -b particle and you get 212 Polonium (HL 3 * 10^-7 seconds) and immediately heads to 208 Lead. 36% Lose an a particle and head to Thallium for ~3 minutes and then throw off another -b particle becoming 208 Lead, which is stable. This liberates 42 MeV per completed decay chain for one atom of Thorium. This is happening constantly. It's admittedly not a monster amount of MeV, however, it doesn't happen one at a time. The main problem is likely the discoloration of the Thorium doped lens element. I just don't like the idea that this wasn't revealed to us till later. I've seen stories of newer lenses still being doped with Thorium (something I'm planning on working on) well past the early 70's. Take this info for what you will. Just remember Thorium is not just an alpha emitter. Quote Link to comment Share on other sites More sharing options...
Creteil78 Posted November 21, 2020 Share Posted November 21, 2020 On 4/26/2014 at 12:13 PM, Junior said: Hi! It's one of my first posts here but not the funniest I guess… I'm not especially talking about a magic C-lens in particular here but about a very underestimated question: radioactive lenses! One of my friends is a fireman captain and introduced me yesterday to one of his colleagues specialized in technological risks and chemical dangers (at Poissy, France : they're known to have very great equipments.) We made 3 different tests on all my Russian lenses which are all OK excepted the Mamiya Sekor 55mm f1.4 (M42). Here are the results: From 5 to 10 µSV per hour (by direct touch), and 1720 shocks per second. Element involved is Thorium 232. They told I really shouldn't keep it. Work with it more than one hour is dangerous. It must be gifted to specialized services and absolutely not be destroyed! Or thrashed! The most dangerous exposure isn't even radiations but dusts to inhalate or ingerate (when a lens gets old it disaggregates - it's something you can't always clearly see). I'm lucky cause until today I kept it in my basement. So, say it please to your friends and all potential Mamiya/Takumar users that you know via websites etc, it's a strong matter of health. i sent you a MP. if you are willing to discuss those topics. Quote Link to comment Share on other sites More sharing options...
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