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Fungus
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PostPosted: Sat Apr 26, 2014 2:04 pm    Post subject: Fungus Reply with quote

Apart from the sun (of which we see very little in this part of N Wales) what other sources are there of UV light to kill fungus?
TIA


PostPosted: Sat Apr 26, 2014 3:03 pm    Post subject: Reply with quote

UV lamps, the ones you can get from pet stores (for reptiles).
But since UV light is often blockes by the glass elements, success is not guaranteed.


PostPosted: Tue Apr 29, 2014 12:24 pm    Post subject: Reply with quote

UV LEDs maybe worth a try? They have more focused light, so you can direct them into the lens.


PostPosted: Tue Apr 29, 2014 1:44 pm    Post subject: Reply with quote

I use a small UV fluo lamp of 4W, it was formerly used to erase EPROM memories. Similar lamps were used for chirurgical equipment disinfection.

It's like a standard fluo. You have only to add a ballast and a starter and put it into a tight closure box, with a switch on the lid so the UV lamp gets disconnected when you pull the lid up. UV radiation is very dangerous for the human eyes, may easily harm the retinae.

Regards.
Jes.


PostPosted: Tue Apr 29, 2014 9:02 pm    Post subject: Reply with quote

Well keeping a lens in a dry place and the fungus wont get worse and will die eventually, but I suppose you want to kill it ASAP.


PostPosted: Wed Apr 30, 2014 8:50 am    Post subject: Reply with quote

Personally I cannot see any in my lens, a Vivitar 19mm. But having had it returned by a buyer as having fungus I thought Id check. BTW. he used a Canon eos 5iii with an adapter, my lens is in FD fitting.


PostPosted: Wed Apr 30, 2014 11:27 am    Post subject: Reply with quote

trev wrote:
Personally I cannot see any in my lens, a Vivitar 19mm. But having had it returned by a buyer as having fungus I thought Id check. BTW. he used a Canon eos 5iii with an adapter, my lens is in FD fitting.


Shame the buyer doesn't come to this forum as I'm sure we all agree that a bit of fungus or dust doesn't make any difference in results....maybe he was a collector\investor and wanted a perfect lens. Rolling Eyes h'mm and surely a fd lens will not work on a EOS mount, and another reason why he should come here.


PostPosted: Wed Apr 30, 2014 12:36 pm    Post subject: Reply with quote

Lens is more or less like new - he said that the lens caused some "fuzzyness" around the edges.
Lens can be used on eos cameras with appropriate adapter which causes a loss of detail though.

I have an oldish vivitar series 1 19-35 af lens which I used on my 1n, the front element is scratched but it doesnt cause any loss of detail provided I keep the sun (a rarity here) out of the frame.


PostPosted: Wed Apr 30, 2014 9:56 pm    Post subject: Reply with quote

One thing to bear in mind with fungus when killing it via UV: It takes a LOT of UV, so a tanning bed is a good option. I did this with a lens and afterward the fungus stopped growing for six months. Then new spots appeared and grew even faster.

Mold colonies release chemicals called mycotoxins. These chemicals are sort of like chemical armies that fight other mold colonies to keep them from growing. So when the original mold colony died, it stopped releasing mycotoxins. The fungal spores on the lens that had been held in check then went crazy and a number of new colonies grew. This caused an imbalance that led to more fungal growth and more colonies and caused a lens that was otherwise okay to have enough fungus that the performance was impaired.

Oops.


PostPosted: Wed Apr 30, 2014 10:25 pm    Post subject: Reply with quote

From the Carl Zeiss website -

http://www.zeiss.com/camera-lenses/en_de/website/service/fungus_on_lenses.html

Service Info:Zeiss
Fungus On Lenses

Fungus means an Infestation of optical instruments with fungus spores which germinate and produce more spores.
Lens surfaces are irreparably damaged by metabolic products of the fungus (e.g. acids). Its damage ranges from cloudiness to opacity caused by the film. The Carl Zeiss T* coating has no significant influence on fungus growth or generation of spores.

Where does fungus come from?

Fungus spores are everywhere and germinate under suitable environmental conditions:

Growing conditions
Relative humidity of at least 70% (more than 3 days)
No or little airflow
Darkness
Nutrients (textile lint, traces of grease, varnish, dust and dirt)
Temperatures between 10 and 35°C

How can fungus be avoided?

Reduce the relative humidity to less than 60% (never under 30% as it is dangerous for the instrument) by storing:

in climate-control cabinets in which hygrometers maintain environmental conditions
next to driers (e.g. silicagel orange packs) in the containers
in a special cabinet whose interior is heated to 40°C (max. 50°C) using a fan heater/ incandescent lamps, thereby reducing the relative humidity
in hermetically sealed cabinets with fungicides with high vapor pressure (fungicide depot must be replaced at regular intervals)
in an dehydrator above driers

After the work is done, Immediately clean the instruments. If possible, you can use a fan to facilitate evaporation of surface moisture. Do not use containers made of leather, textiles or wood for storage. Short solar radiation or irradiation with UV light may also help avoiding fungus.

How can fungus be removed?

Note: In general, Carl Zeiss does not accept instruments infested by fungus.

Clean affected surfaces with a cotton wiper that has been soaked with a disinfectant. You can build your cotton wiper, using cotton wrapped around a toothpickin such a way that a ball with a peak forms on the pointy end of the stick. Use pure cotton, no prepared or impregnated cotton. Strongly rub slightly corroded optical surfaces with an optical cleaning cloth, cigarette ash can be used as a polishing aid. Heavily corroded optical surfaces must be replaced. Fungus infestation in the interior of an instrument can only be eliminated through disassembly of the instrument.