TP: Protect your Lenses from Fungus

OK- some more on fungus- questions not answers, I mean. There really doesn't seem to be any established science on this. I live in Durban- Average humidity >80 for seven months and never less than 70, Ave temp usually mid twenties(C)and never less than 18. I have a newish (October 2013 Sony 18-250) which has hardly been off my A65 since I got it, and it's used a couple of times a week on average. It has never been allowed to get wet, and camera and lens are kept in a backpack with a few other lenses. To my horror, a few days ago, the first tentacle of dreaded spiderweb appeared, dead centre on the front glass. To their credit, the local Sony shop were equally horrified and it's been sent to Dubai (apparently their Middle East and Africa service centre is there) for repair under warranty.
A quick check on my other lenses, and there's a little spot on the edge of my cherished beercan series 35-105 (kept in the backpack), and a serious infestation in my rarish (in SA)100-200 Macro last used in winter in Canada a little more than a year ago and stored separately with the rest of my collection. Also I've just paid to have a Sigma 400 cleaned.
So I'm ready to try anything, but the dry cabinet is a little beyond budget.
Something struck me from earlier posts- Leica-M and another poster seem to indicate that lens fungus doesn't happen in Scandinavia, which makes me wonder if, besides humidity, there is a temperature below which the fungus cannot survive? i.e. if one put a lens in the freezer for a short time- would that kill the fungus?

Thanks and point taken. I'll have to check for local availability and price. I'm also going to investigate UV lighting and as an experiment have a crack at a 70-210 beercan which came in a bundle and which had more fungus than an Italian forest in autumn and is beyond saving.
In SA we have a local delicacy called biltong- dried meat, similar to jerky. I was recently given a cabinet for making it, which consists of 4 well ventilated clear plastic sides, a 40w incandescent light bulb and a PC fan to circulate warm air to cure the beef. I'm not entirely joking when I say I'm considering using it. I just have to find a way to establish whether, besides warming the air, it reduces humidity.

JimD wrote: Thanks and point taken. I'll have to check for local availability and price. I'm also going to investigate UV lighting and as an experiment have a crack at a 70-210 beercan which came in a bundle and which had more fungus than an Italian forest in autumn and is beyond saving.

Just in case you're not aware of this, the fungus will still be visibly present even if you kill it, it just won't grow any more. You'll have to open up the lens and clean it out if you really want to test it.

One "fun" way of testing whether you've killed the fungus is to clean only half of the front element. Then let it sit for 2-4 weeks and see if anything has grown on the clear half. Of course, that requires keeping the lens in storage conditions that will allow fungus to grow, which might just cause reinfection, even if you were successful...

One of my lenses had a thoriated element (the Canon FD 35mm f2 oldest version), so I was seeking a UV solution because it was getting too hot to have the sun do it. I came across this bulb after searching for a long time on various methods (the IKEA lamp one did not work for me)

http://www.amazon.com/Exo-Terra-Repti-Glo-Fluorescent-Terrarium/dp/B00101GDIG/ref=sr_1_6?ie=UTF8&qid=1399398833&sr=8-6&keywords=reptile+bulb

I plugged it in to a regular lamp, and had the lens sit under the bulb for about a week. It got rid of all the yellowing, which the previous IKEA lamp and a few weeks in the sun did not do!

I think if the UV is powerful enough to deyellow thoriated glass, then it is possible that it can kill fungus enough to stop the further spreading. I have had a few fungal lenses placed under it for a bit of time, though I can't really measure my results. My storage conditions are cold and dry so I doubt I would see any growth anyway (any lenses that do have growth were bought from others). Just thought this info might help!

A dry box (humidity controlled cabinet) seems to not allow fungi to grow. Set it to 40% humidity. If set lower it apparently makes the lubricants in the lenses dry out.

I use to keep lenses in a sealed camera bag with silica gel but when the gel became saturated fungi would start in some lenses. Since using a dry box (for about 4 years) there have been no fungi issues. A dry box is much less hassle as you do not have to muck around with plastic bags, silica gel, etc, ypu just plug it it in and it takes care of itself.

Just my 2 cents.

From everything I have read and observed warmth, moisture, a bit of oxygen and a growing medium are what is needed for most forms of fungus to thrive. An absence of light (UV especially) also seems to help fungus grow. Photosynthesis, unlike for other plants and algae, is not necessary for fungal survival. Think mushroom farms.
In a hot, humid subtropical coastal climate there is plenty of warmth, moisture and oxygen. The lens coatings appear to provide a growth medium. Storing a lens in the dark after it has been used in this climate seems to be a sure-fire way of getting fungus in the lens. Even leaving the lens caps and a UV filter on seems to help the fungus grow.
What you want is to create conditions inimical to fungus, the opposite of warm, moist and dark, i.e. cold, dry and light, preferably UV.
I am busy looking at ways of creating these conditions for lens storage without going to extremes- too cold, too dry or too much UV will probably harm the lenses as much as fungus. To create all three is theoretically possible but only at vast expense.
Cold is difficult (I can't see my wife ceding the fridge space) and problematic with condensation when you move the lens into a warm environment, dry is achievable at some expense, but a UV lamp will cost very little. So, I'm looking at buying/building a dry cabinet with a UV light source.

Coming to your query, moving a lens from an AC (cold) environment to a humid outdoors will certainly get the necessary moisture into your lens. You've seen it. I guess it's what happens afterwards that matters. i.e. warmth and light. If it goes back into the AC environment, and is kept in a light airy space with filters and caps off, that should help. In NJ, I'd guess the winters are cold with dry air (exceptionally so when I visited the US last year), so your problem is seasonal.

So, going back to the first post in this string, about storage, the suggestions regarding sealing and silica are valid, provided you can be sure that all moisture has been extracted before sealing. The suggestions that caps and UV filters remain on and the lens be stored in its case will exclude UV light and are IMH actually more likely to promote than prevent fungus.