Issuu is a digital publishing platform that makes it simple to publish magazines, catalogs, newspapers, books, and more online. Easily share your publications and get. Voigtlander Camera Serial Numbers' title='Voigtlander Camera Serial Numbers' />Radioactive lenses. Radioactive. Glass in Lenses. Are Your Lenses Really Hot Robert MonaghanThe titles of the original. Related Local Links are included but no longer linked to. Related Local Links Fallout Shelters, Radiation. Industar 6. 1 lens lanthanum glassLens Faults Pages. Photo. Net on Radioactive Lenses gamma levels. Radioactive Fed 5s slight. Radioactive Optics Posting WJMRadioactive Pentax Lens GM tube sound file. Romancing the Rare Earths. On Enhancing Filters by Howard Ross. U. S. Govt Surplus Hot Cameras and Lenses. You will find two kinds of radioactive. If you want to buy some slightly radioactive lenses and cameras, the. U. S. Government has a lot ofthem for sale cheap Maybe some of those bargains you got on EBAY. I am assuming that heavily contaminated. So if your government surplus bargain camera or lens is. Thats good news, I guessShop from the worlds largest selection and best deals for Film Cameras. Shop with confidence on eBay Strobe Trigger Voltages Is your old strobe safe to use on your new camera Photography news and headlines from across the web. Shop from the worlds largest selection and best deals for Rangefinder Film Cameras. Shop with confidence on eBay The Voigtlander 75mm f1. It feels great, has swell bokeh, is very well made, handles well, focuses. Home Camera Articles FOR SALE Orders I Buy Wants Repairs Books Adapters Contax II and III. Zeiss Successful Leica Competitor. Our main focus here is not on contaminated lenses or cameras, but on. Hot Lenses made from Radioactive Materials. Many specialty optical glasses have radioactive elements added to them. These slightly. radioactive elements suchas thorium or rare earth elements such as lanthanum were used to produce. Acpi Ifx0102 1 Driver Hp. Other uses for rare earth elements in photography include color enhancing. See Howard G. Ross Romancing the Rare Earths for a history of enhancing filters and. Radioactive Elements in Glass. Thorium is derived commercially from certain monazite sands e. India. Thorium isradioactive itself, emitting alpha particles. The resulting daughter. Related rare. earth such as lanthanum areoften produced from the same sources, with monazite being up to 2. This decay process means these thoriated glass lenses can gradually. This result is counterintuitive. You would expect the radioactivity to decrease over time. But after. chemically purifyingthe thorium from its ore sources, the thorium is relatively free of. Overtime, the thorium decays, and the levels of radioactive daughter by products. Eventuallya more highly radioactive equilibrium will be reached, as in the original. So overthe years, your hot lenses are likely to get more radioactive. Surprise Lanthanum has two isotopes in its natural form, one of which is weakly. Anothersource of rare earths such as lanthanum is cerite, which contains the. Cheapglasses may have iron salts in them, often yielding the familiar green. Cerium is often added to glass to convert iron. Unfortunately. the rare earths includesome chemically very similar elements as contaminants, many of which. The chemistry of lanthanum and its associated rare earths is so closely. The amount of such contaminants could also easily vary. I dont think that the original levels of thorium or lanthanum specified. Later lenses. of the same exact design and glassformulas, but from later batches with higher serial numbers, do not. Nor do they suffer from yellow discoloration over decades. So it isnt thethorium or the lanthanum that causes the problem here. The radioactivity. It isthese radioactive contaminants which cause these lenses to be more radioactive. However, dont assume that all yellow lenses are necessarily radioactive. Many lenses turn yellowdue to aging of the Canada Balsam adhesives used to glue lenses together. Other lenses may havecoloration biases which make them slightly yellowish rather than clear. But if you. have a lens using early specialty glasses wide angles, fast lenses. Most school physicslabs can do this, as can local Civil Defense offices and police or fire. Voigtlander Camera Serial Numbers' title='Voigtlander Camera Serial Numbers' />Voigtlnder was one of the the worlds longestlived camera and lens makers. The brand is still used by other firms. Nikon has long used the first digit of the serial number to indicate region for many of their products. Traditionally, that first digit was used like this. Another important point here is that these contamination levels vary. Soyou have to test each lens to determine if it is radioactive, and how. Tests of one lens from one batch wont apply to another lens made from. You have. to test each lens to be sure. Roger Hicks on Radioactive. Lenses Radioactivity in the first generation of hot lenses c. There are quite. a few hot rare earth firstgenerationlenses. Radioactivity in the second generation of lenses was down to the use. Once. again, the purity of the cerium wasquestionable. These are alpha particle emitters, which aint normally a problem. These second generation lenses stretched well into the 1. Takumars was hot. Source Bob Shell 2. Sept. 1. 99. 9 posting below quoting Mr. Roger Hicks. noted author of The Lens Book etc. Radioactivity. Radioactivity generally is found in three categories alpha particles. The xray and gamma radiation is very penetrating, able. Alpha particles can only go through a few inches of air, and are stopped. Butthey can interact strongly with the surface of the cornea of the eye. This event happens when an alpha particle emitter is used in. Such exposures can produce cancers and radiation. Beta particles can penetrate a few feet in air, or a range of thicknesses. The beta particle emitters are most important photographically. Beta particles canpenetrate camera shutters and film cassettes to fog film next to radioactively. Gamma and xrays can do so too, but their intensity. Examples of Potential Hot Lenses. Examples of likely hot or radioactive lenses include Kodak. Aero Ektars 6, 1. Canon Pellix 5. 0mm lens, the Asahi Pentax 5. Leica 3. 5mm f2summicron. Not all examples of any given lens type will necessarily. Differentbatches may have been made with glass from different sources. The amount. of radioactivecontaminants may have also varied between different lens batches too. See our Ektar lenses pages for listing of some of the many Ektar lenses. Similarly, see our 4x. APO Lanthar lenses by. Voigtlander and a listing of Tessar derivatives. The lanthar. in the Voigtlander lens nameevidently originated from the Lanthanum used to create the needed high. Again, not all Lanthar lenses. Lanthanum Glass in Widespread Use. There are an awful lot of lenses with lanthanum glass in them. Lanthanum. crown glasses weredeveloped by Morey at the NBS in the mid 1. Kodak whoproduced several Lanthanum glasses. They were applied to a wide variety. Ektar series of Tessar type lenses. There are likely few. Lanthanum glass. It was one of the first high. Source Richard Knoppow, see posting of 2. Sept 1. 99. 9 below. The major direct impact of radioactivity on lenses is limited to the. But these changes can. Some radiation dose monitors use such particle. However, the early glass formulas and contaminated chemicals used have. This yellowing is related. Seeour lens color pages for tips on how to test your lenses for this thorium. Testing for Radioactivity in Lenses. You can easily test a suspect lens using a sheet of high speed polaroid. Placethe lens glass element facing downward onto the polaroid sheet for a. Ifyou see a foggy shadow or outline, you have a radioactive lens. You. can also use longer exposuretimes with a sheet of photographic paper from your darkroom, provided. This photographic approach was how nuclear radiation was first detected. Becquerel, thanks toa fogged photographic plate placed near a sample of uranium ore. The. trick still works. You canalso use a standard geiger muller counter or other instrument able to. Danger Assessment Just how radioactive are typical hot lensesStudies of. Leica lenses see postingsbelow came up with 1. This figure compares to 2. But that 2. 0. mrem is for whole bodyexposure, while the lenses mostly emit shorter range beta and alpha. On the other hand,it may take just a single gamma ray to turn one of your cells into a. These 1. 5 mremhr levels are surprisingly high compared to typical. Dont tell OSHA or the EPA, or all those collectible Leica lenses may.