Lens Fungus, how to avoid it and does it really matter in the normal attention span?

tikkathreebarrel

tikkathreebarrel

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I absolutely get it that "heritage/vintage/legacy" lenses can be spoiled by the presence of fungus. I'd rather buy a lens without fungus over a lens with fungus and I'd rather prevent any of my lenses from contracting fungal infection.

I don't belong to a camera club so I get all my sage advice & opinions from t'internet and it was reading online last week that storing lenses in the sunshine is the right thing to do which got me wondering.

Lens cases which keep the light out, lens caps front and back, honestly they seem counter-intuitive to the suggestion of letting daylight stream through the lens.

So here's my question: modern glass does it get fungus, how long does it take and what are the optimum conditions for avoiding it?

Who even bothers about it?
 
The most important thing to avoid is damp, so avoid humid areas and be sure to store your kit somewhere dry.

Sunlight is to be avoided for most plastics due to a process called actinism that breaks it down at a molecular level.
 
I keep my old lenses in old biscuit tine lined with bubble wrap and include some gel packs. I've never seen any fungus to date.
 
I bother about it and don't want it! So I take good care of my kit and make sure it's clean and dry after each time I use it, and I store it in a dry location which avoids sudden changes in temperature (which can cause condensation). Lens fungal infections can vary in severity, with some actually etching into the surface of the glass and coatings, causing permanent and irreparable damage to the lens elements. I certainly wouldn't knowingly buy a lens that was affected by fungus to add to my camera bag - in fact I wouldn't even risk one for free! I know fungal spores are all around us, but why encourage or add to that situation.
 
Now, I'm not a lens expert, but I am a biologist by training. For a fungus to live, it needs food and water. They don't eat glass, the damage is just a result of their metabolic byproducts. Old lenses used to be stuck together with yummy Canada Balsam. Modern lenses are not. Keep them clean and dry and they ought to stay fungus free. Prolonged exposure to sunlight breaks down plastics, quite possibly lens glue as well and subjects the lens to a hot/cold cycle that I'm willing to bet won't help it's longevity.
 
Most lenses get specks of dust inside and it's usually organic origin - that will start fungus off.

While our houses are generally dry enough risk factors are putting them away in a bag slightly damp for a few weeks,.
Summer is probably more risky than 'damp' winter, with no heat on for several months.
The dehumidifying gels and such can help but only if you use them in a more or less sealed box, in a cupboard or camera bag they become ineffective in a very short period.

I learnt a lesson early on with my first digital SLR a Canon 300D getting it on the actual sensor when I didn't use it for about a year after upgrading.
 
Raymond Lin said:
Get a Pelican Case, put silica gel in it, job done.
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Ventilation is best. Unless you replace the silica gel with reactivated silca gel everytime you use a lens.
 
A friend of mine left his wife and set up home in new accommodation. During this stressful disruption, he left much of his camera kit in a bag in a room which had dampness. Normally it would have been stored in a dry place with dehumidifying crystals. I think the time passage was at least 6 months before he got back to photography and discovered the fungus which had attacked the camera and several lenses. He had to send the camera and one or more lenses to a specialist to clean. I believe he was able to claim some of the cost from insurance but not all and a couple of lenses he dumped. I would not normally buy a second hand lens and store all my kit in warm dry environment.

Dave
 
john.margetts said:
Ventilation is best. Unless you replace the silica gel with reactivated silca gel everytime you use a lens.
Click to expand...

Let's pose a scenario.

If the humidity is 50% (in the room i am in right now), then put lenses in and silica gel in, it reduce humidity to 10% (or whatever below the threshold where fungus will grow) and I don't open it. Why would fungus grow? Even without ventilation? There simply isn't enough water.

If I am using it all the time, daily, then in theory silica gel is useless since the cases is opened far too often for it to be effective.

Of course using a redundant silica gel is useless, all silica gel give you a sign when they need reactivating or regen, so just do it when it needs to. Ventilation comes when you come to use the lens.
 
Raymond Lin said:
Let's pose a scenario.

If the humidity is 50% (in the room i am in right now), then put lenses in and silica gel in, it reduce humidity to 10% (or whatever below the threshold where fungus will grow) and I don't open it. Why would fungus grow? Even without ventilation? There simply isn't enough water.

If I am using it all the time, daily, then in theory silica gel is useless since the cases is opened far too often for it to be effective.

Of course using a redundant silica gel is useless, all silica gel give you a sign when they need reactivating or regen, so just do it when it needs to. Ventilation comes when you come to use the lens.
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Two questions: how much silica gel does it take to reduce the humidity in your case to 10% (and how do you know that the amount you use does)? How long does it take the amount of silica gel that you are using to reduce the humidity from 50% to 10%?
 
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john.margetts said:
Two questions: how much silica gel does it take to reduce the humidity in your case to 10% (and how do you know that the amount you use does)? How long does it take the amount of silica gel that you are using to reduce the humidity from 50% to 10%?
Click to expand...

Answer - I have no idea, I do know that I have not even used silica gel with a pelican case for the past 15 years and I get no figus. Adding a silica gel is not going to increase humidity.

Also, I have a hygrometer in my house (because I have guitars), and the room is always between 44-55%.

I presume we all live in the UK and I presume we all live in an average house with average insulation with central heating and I presume we don't store our cameras under the sink but in a habitable room along with everything else.

I could make a SOLID argument ventilation isn't best method, plenty of fungus grow out in my garden where it is 100% fully ventilated. Or people who live in tropical area, leaving gear out around the room "ventilated" will introduce fungus and they often need to buy a dehumidifier storage for their gear, my cousin who lives in HK has one for example where the average summer humidity is in the 80% during the summer. But I am not going to make that argument since we don't keep our gear in the garden and I don't think we live in HK, I am merely illustrating the point that "ventilation is best" is not the right approach for everyone. The right approach is to minimise humidity, if it's in a case stored in a room that you live in, adding a silica gel can only LOWER humidity, not increase it.

The alternative is get a dehumidifier for the room it is stored in.
 
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Or buy a special dry cabinet like I have which uses about 2w by USB and makes a nice display with internal light if you want.
Digital readout on the front, it's 34% usually.
Below 30% is actually not good either I guess you might 'dry out' seals or something.

Mine was under £100 which seems reasonable for £5K plus of gear and you can even lock it.
 
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