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F16sunshyn
Tinkerer
Username: F16sunshyn
Post Number: 19
Registered: 05-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, October 04, 2007 - 10:36 pm: | 
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This is a response to a earlier question from RJ. I thought it could be a subject for a new thread. A freind of mine who has the camera disease also, has a system for getting rid of odors in older cameras, and yellowing in thoriated lenses. It is a product called Air Lazer. It is made for greenhouse and restuarant use. The Air Lazor is a UV light fitted into a small fan driven box. The fan pushes air past a uv bulb that produces 03. In a smelly setting like a pub or geenhouse it kills odors. James uses it to kill fungus and de-yellow lenses. I recently checked out his setup and it looks like this. The Air Lazor is a aluminum box about a half meter by 12cm. When you remove the top cover the bulb and reflector are exposed. He puts a small metal grid over the bulb, places the suspect lenses or leather cases on it, and leaves the unit on for a few days- 1 week ( a BBQ for cam gear). Yellowing from thoriated lenses is gone in a few days. Smoke and must smell in leather in a week or so. This thing stinks (only when running). It has a similar smell to old Zerox copy machines. You should NOT USE IT IN THE HOUSE. 03 is bad for organic creatures, like humans (that is why it kills fungus). I tried it over the last week with a old tomioka 55 1.2 that was quite yellow, it is now clear. After looking for info about the bulb's actual nm output I found nothing. Sorry RJ, I only found this product in 110 60hz. It is however very effective and probaly worth the effort to convert to 220. Constant rotation of the lens seems like it is the right thing to do. I hope this will help someone. Certainly there is a simpler way (the sun) this may be faster and more controlable. Die fungus Die. Best of luck
Andy |
Wernerjb
Tinkerer
Username: Wernerjb
Post Number: 200
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 05, 2007 - 02:04 am: |
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In my house I have several windows fitted with so-called thermopane window glass, these were sealed metal frame windows when they were made, but have lost their vacuum over time and are now at least open to fungus spores. Why am I telling you all this? Because inside that former vacuum these windows are the dwelling place for large colonies of fungus that thrive in full sunlight. Being an aquarist and hobby fish breeder who uses UV light to reduce the number of germs in the breeding tanks, I can also tell you that UV light will kill certain types of germs, but definitely not all of the fungus types there are, W. |
605er
Tinkerer
Username: 605er
Post Number: 14
Registered: 08-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, October 06, 2007 - 10:37 am: |
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http://en.wikipedia.org/wiki/Ozone
Has a bit on UV light based ozone generator systems.
You really should read
http://www.epa.gov/iaq/pubs/ozonegen.html
before considering ozone for removing orders in inhabited areas. |
Rj_
Tinkerer
Username: Rj_
Post Number: 38
Registered: 08-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, October 06, 2007 - 11:34 am: |
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Hi F16
thanks for following up. Can't believe I missed this thread almost. Seems like some of best things come wired for 110 volts.
It seems like a unit which requires a degree of discipline and management. I'm familiar with working with toxic chemicals and the discipline required for use of a UV/Ozone generator like this makes sense for small applications. It even seems less hazardous than the use of some solvents, toners and hydrogen peroxide.
The government guidelines for ozone units seems to pertain to larger spaces, particularly breathing spaces and air cleaners, and not specifically targetted at the micro-applications such as lens cleaning.
Unfortunately (?)the only type of fungus I come into regular contact are shitake and onnochi or chesnut mushrooms. My lenses don't justify requiring this kind of ozone removal although the light source is fascinating for its application.
I do have a Cooke Apotal lens by the window which, despite 6 months in the sun, retains it's brassy colour in the lens instead of being clear. Would love to see if it would ever clear.
Many thanks for the insightful post.
Kind regards,
RJ |
Glenn
Tinkerer
Username: Glenn
Post Number: 189
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, October 06, 2007 - 05:42 pm: |
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There are far more efficient deodorizing products available from undertaker's/funeral director's supply houses, than using ozone generators. The powder products are very simple to use and do not even have to come into contact with the camera or case. Just use a sealed box and a small amount of powder in the bottom.
I can find no scientific evidence that ozone removes yellowing from thoriated lens elements, though I stand to be corrected on this. The use of ozone to kill fungus inside an assembled lens, must be considered a hit and miss affair at best.
I suspect that any removal of yellowing, will be down purely to exposure to the UV. It should also be noted that wavelength plays a very important role in this process, and any fungus removal that may occur. |
Glenn
Tinkerer
Username: Glenn
Post Number: 191
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, October 07, 2007 - 06:33 pm: |
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I should have also added the following to yesterdays comments.
Ozone can be very detrimental to items made from natural rubber compounds. Items made from these compounds, can suffer from a condition called 'ozone cracking'. If a stressed - stretched or compressed - rubber component is exposed to high concentrations of ozone, the surface of the item will start to harden and crack. My old employer found this out the hard way. Large numbers of rubber insulated cables were held tightly together with cable ties, in environments that were subject to high levels of ozone. During a major component upgrade, the insulation on these safety critical cables was found to be full of fine cracks around the ties. The insulation being so degraded that it fell off when the bundles were separated.
UV lamps are used in the accelerated weathering chambers, used to test the fade resistance of fabrics, paints, plastics and many other products.
So 'cooking' a fungus infested lens (with a rubber focus ring grip) and the nicely coloured (but smelly) leather case that came with it in a UV powered ozone generator, might just leave you with a badly faded case and a disintegrating focus grip. |
Rj_
Tinkerer
Username: Rj_
Post Number: 42
Registered: 08-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, October 07, 2007 - 07:39 pm: |
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Thank you for the update Glenn.
I do think that f16sunshine was posting specifically about UV light sources, and the digression towards ozone generators is a separate issue although 'UV based ozone generators' seem to move towards a more toxic level.
If the issue of ozone generators is left aside for a moment, maybe there are safe applications for UV lightsources? Hand-held UV detectors are regularly in use. Perhaps short pulses of UV light are safer for brass lenses - which may tolerate the UV treatment with no adversity if there is any concern about plastic disintegration.
I'm curious, partly because I can see no solution for the non-fungus related issue of the thoriated Taylor Hobson lens which currently is not much use to anyone unless dethoriated.
Kind regards,
RJ |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 397
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, October 07, 2007 - 08:21 pm: |
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Sunshine is a pretty reliable UV source |
F16sunshyn
Tinkerer
Username: F16sunshyn
Post Number: 20
Registered: 05-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 08, 2007 - 09:07 am: |
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Rj is correct. This post is more about a good UV light source than ozone. It's true there is a enough ozone produced by this small bulb to help reduce/eliminate odor. The bulb is warm but not hot when running. This fact allows you to place a lens very close to it. The results I observed with my old Tomioka where very impresive (clear in 1 week). I have used the sun for clearing a Super Takumar. It took nearly the whole summer to clear up,it did work quite well however. As for fungus. This method will not clear a lens that has growth. UV light in such constant supply will stop growth and kill small patches and spores. The idea is to make a hostile environment for the fungus. A period of 48-100 straight hours of intense UV would be tough for many organisms. I don't think it is realistic to compare the environment of a window or windowsill. Fluctuations in temp, humidity, and dark periods will provide a condition where foci can colonize and overcome the suns effect. As I stated in the original post. This is not something that should be done in a living area. The ozone that is produced stinks and is very unhealthy. For me the expense of this unit is not worth it. I rarely come across yellowing or fungus. Rick is right, the sun does provide reliable UV. I will use it in the future if the needed for de-yellowing (I can also use my friends arangement). For someone who works with a lot of older Pentax glass for example. This could be a very valuable tool and time saver. Shitakes sound good it's time for lunch. |
Charlie
Tinkerer
Username: Charlie
Post Number: 104
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 08, 2007 - 06:24 pm: |
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I have seen advertising brochures for cameras where the anti reflection coating is yellow. |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 398
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 08, 2007 - 07:09 pm: |
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Actually, all antireflection coatings are colorless. Only the reflections off of them have a color, due to the thickness of the coating... if you look through the coated lens it is clear. A yellowed lens, on the other hand, looks yellow when you look through it. |
Mndean
Tinkerer
Username: Mndean
Post Number: 30
Registered: 08-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 10, 2007 - 04:22 pm: |
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I just got a lens with radioactive glass (Minolta Rokkor 28/2.5), and found it has mild yellowing. While I generally would like the idea of leaving it on a windowsill, the amount of heat the lens will receive worries me a little as does the amount of dust that may settle on and in the lens for the length of time it stays while clearing. The UV lamp idea is not bad - it provides some control re: duration of exposure and environment. Has anyone tried clearing with a regular fluorescent UV lamp? It would also be interesting to know what bandwidth of UV is most effective. |
Rj_
Tinkerer
Username: Rj_
Post Number: 48
Registered: 08-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 10, 2007 - 05:03 pm: |
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"Sunshine is a pretty reliable UV source"
Lol Rick - this would appear true, except in England ;)
Andy - is yours like this:
http://ojyamarche.nobody.jp/yashinon5512.html
I wonder if you have had a chance to assess its prints since dethoriation. I had always assumed the colouring was part of the multicoating, however Rick's point makes it important for the lens to be inspected visually, instead of assessed by a .jpg which is the only means by which I've seen this legendary lens.
Mndean - I've tried leaving the Taylor Hobson lens in front of a daylight halogen bulb for most of last winter season. When that failed and my energy bill escalated, it has since spent over 6 months by an English window. Unfortunately a fluorescent UV lamp would outweigh the cost of the lens. Equally, the lens has accumulated a lot of dust on the window.
I suppose I could have protected it with a UV filter ;)
Nonetheless, it remains thoriated, like most lenses with radioactive components with a half-life of half a century or less.
Perhaps a fluroscent UV lamp source could also double up for alternative processes?
Rj is correct. This post is more about a good UV light source than ozone. It's true there is a enough ozone produced by this small bulb to help reduce/eliminate odor. The bulb is warm but not hot when running. This fact allows you to place a lens very close to it. The results I observed with my old Tomioka where very impresive (clear in 1 week). I have used the sun for clearing a Super Takumar. It took nearly the whole summer to clear up,it did work quite well however. As for fungus. This method will not clear a lens that has growth. UV light in such constant supply will stop growth and kill small patches and spores. The idea is to make a hostile environment for the fungus. A period of 48-100 straight hours of intense UV would be tough for many organisms. I don't think it is realistic to compare the environment of a window or windowsill. Fluctuations in temp, humidity, and dark periods will provide a condition where foci can colonize and overcome the suns effect. As I stated in the original post. This is not something that should be done in a living area. The ozone that is produced stinks and is very unhealthy. For me the expense of this unit is not worth it. I rarely come across yellowing or fungus. Rick is right, the sun does provide reliable UV. I will use it in the future if the needed for de-yellowing (I can also use my friends arangement). For someone who works with a lot of older Pentax glass for example. This could be a very valuable tool and time saver. Shitakes sound good it's time for lunch.
Charlie
New member
Username: Charlie
Post Number: 104
Registered: 07-2006
Posted on Monday, October 08, 2007 - 05:24 pm: Edit Post Delete Post View Post/Check IP Ban Poster IP (Moderator/Admin only)
I have seen advertising brochures for cameras where the anti reflection coating is yellow.
Rick_oleson
New member
Username: Rick_oleson
Post Number: 398
Registered: 07-2006
Posted on Monday, October 08, 2007 - 06:09 pm: Edit Post Delete Post View Post/Check IP Ban Poster IP (Moderator/Admin only)
Actually, all antireflection coatings are colorless. Only the reflections off of them have a color, due to the thickness of the coating... if you look through the coated lens it is clear. A yellowed lens, on the other hand, looks yellow when you look through it.
Mndean
New member
Username: Mndean
Post Number: 30
Registered: 08-2007
Posted on Wednesday, October 10, 2007 - 03:22 pm: Edit Post Delete Post View Post/Check IP Ban Poster IP (Moderator/Admin only)
I just got a lens with radioactive glass (Minolta Rokkor 28/2.5), and found it has mild yellowing. While I generally would like the idea of leaving it on a windowsill, the amount of heat the lens will receive worries me a little as does the amount of dust that may settle on and in the lens for the length of time it stays while clearing. The UV lamp idea is not bad - it provides some control re: duration of exposure and environment. Has anyone tried clearing with a regular fluorescent UV lamp? It would also be interesting to know what bandwidth of UV is most effective. |
Rj_
Tinkerer
Username: Rj_
Post Number: 49
Registered: 08-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 10, 2007 - 05:05 pm: |
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PS sorry - I haven't learnt how to use this editor interface. |
F16sunshyn
Tinkerer
Username: F16sunshyn
Post Number: 21
Registered: 05-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 10, 2007 - 07:30 pm: |
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Sunshine does seem to take a fair bit of patience. The Tomioka lens I cleared with the UV bulb was actually label Reuveonon (german re-label of the same lens). I had a Yashica branded model but sold it(it was clear). The only lens I cleared in the sun was a super takumar 50 1.4. I put a P filter (clear filter) on for protection from dust and yuck. A UV filter may actually slow the process as UV is what is breaking down the effects of thoriation. As for heat, foil around the lens makes a huge difference and will provide good protection in most climes. The link at the end is a short list of thoriated lenses. It has some info as to the radioactivity of each lens. I think this may lead to false conclusions as to the lenses that may have the most yellowing. There are other elements at play here that should be considered. A lens that is stuck in a bag for years, will be more effected than one that is in a display case or in active use. Sorry for the length of the link.It has a translator built in (the original is in german). Oddly this is a topic of the now. I just posted this link in another forum yesterday. None of us should be discouraged by thoriated glass. If you primarlily shoot B+W it is hard to notice the yellowing in most normal cases. Also DIGI shooters can adjust the WB to compensate in most cases or catch it in PP. We all have many lens choices, waiting a few months for another one, is a good time to get more familiar with the ones that are ready to play now. Patience, Oh if only my wife had some. Ooopps, Sorry wrong forum.
http://translate.google.com/translate?u=http%3A%2F%2Fphoto.6six6.de%2FYashica_Ob jektiv_Radioaktivitaet.html&langpair=de%7Cen&hl=de&ie=UTF-8&oe=UTF-8&prev=%2Flan guage_tools |
Mndean
Tinkerer
Username: Mndean
Post Number: 31
Registered: 08-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 10, 2007 - 11:47 pm: |
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I certainly wasn't discouraged by thoriated glass - I bought mine knowing full well what it was, and I will likely buy the 58/1.2 MC Rokkor lens (another thoriated glass lens) fairly soon as well. For fast lenses, it doesn't seem to discourage buyers at all. This really is an interesting subject, and the German site shows some surprising results, but unfortunately it doesn't cover Minolta equipment. It would be nice to have a site that cataloged all the radioactive lenses made, and how hot they are. |
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