Lens fungus prevention

[Dave_S]

Out of interest, what do you guys do, if anything, to protect against fungus forming on lens coatings, when not in regular use?

The question was prompted by a discussion about this problem on another forum.

The lenses that people had the problem with, were all Sigma, which is quite ironic, as the only lens I ever had, where fungus formed between the elements, was a Sigma.

I'm sure the problem is not exclusive to Sigma, albeit Sigma lenses do seem to feature prominently in this respect.

It is the lens coating that attracts the formation of fungus, which then eats into the coating, and so can't be removed by cleaning.

The Sigma lens that I had the problem with, was little used, and stored in its foam lined case, kept zipped up, and stored indoors.

Silica Gel is the most commonly used desiccant, a sachet of which is usually included in the packaging of new cameras and lenses.

Do you leave bags of Silica Gel in your camera/lens bag, and if so, how often do you think to regenerate them (heat them in an oven/microwave).

A word of warning: While white Silica Gel is non-toxic (albeit not to be ingested), the type that is Blue when dry, and Pink when no longer effective (has absorbed its maximum amount of moisture), is coated with Cobalt Chloride, and is classified as a Carcinogen.

Dave

[DeeGee]

Re: Lens fungus prevention

I usually drop the silica packets in to my storage bag and as everything I buy recently seems to contain silica bags, even handbags and purses I put these in too. I take the silica bags out and dry them on a hot windowsill in the sunshine on the radiator roughly monthly or when ever I think about it. I figure while it may not be the ratio that some say silica needs to be, its better than nothing. :smile:

Other than that, I don't put equipment away damp. I make sure its well air dry and I make sure that I keep my camera bags in a reasonable area. Not shoved in a damp room with no air flow. If that makes sense. :smile:

[Dave_S]

Re: Lens fungus prevention

The Sigma lens that I had a fungus problem with, never saw any damp conditions, and the few times that it was used, was in the garden on nice sunny summer days.

After that, it was put into its case, zipped up, and kept in my study, which is heated along with the rest of the house over the colder months.

I guess the fungus must be able to form in normal indoor humidity levels, which other than enclosing Silica Gel packs with it, there's not much else that can be done by us, the end user.

All-in-all, its a pretty poor show, that manufacturers can't, or won't, prevent the problem from occurring in the first place, especially given the price we pay for their kit.

Ironically, the optics in my telescopes, which live out in the observatory all year round, without any humidity protection, are fine, even after several years in this environment. These all have coated lenses, just as do our camera lenses.

As much as I like Sigma optics, I would now think twice before buying another Sigma lens.

Dave

[Nathaniel]

Re: Lens fungus prevention

A good question and I believe this was discussed some time ago. So far I haven't had any fungus/mould problems. Yes, I also leave silica gel packets inside my two hold alls where my lenses and camera bodies are kept. I keep the holdalls inside my wardrobe- which is dry but well ventilated because of sliding doors. Ocasionally I dry the silca gels inside the oven- short bursts . I also leave my camera equipment out on ,my bed or settee after a shoot- whether indoors or outdoors. I have had Sigma lenses- the 10-20mm and the 15-30mm and have had no problems with mould or fungus. All my lenses are protected with a UV/Skylight filter after purchase.

(I might mention that when I worked in Africa, the silica gel packets were pink when full of humidity and blue when dry. I used to warm them in the oven when the crystals were pink. I did not have any fungus trouble even there).

Maybe this is an overkill but I hope this helps.

[colin C]

Re: Lens fungus prevention

Fungal spores are everywhere and their preferred environment are some heat and some damp. Condensation will form when you take the lens from a cold to a warm room and if you then put it into a sealed container, that internal condensation that you probably cannot even see, will be the growth medium for the fungal spores.

Good ventilation is your most useful ally against fungus and if you can add some new/refreshed silica gel in a decent enough quantity, that is your next best option. We are realistically talking about a pack of silica gel the size of your computer mouse to be really effective, rather than the sugar sachet that we are all accustomed to. I always "air" my equipment off in my room for an hour or so, before cleaning, re-charging batteries and putting away. Since using this regime, I have never had a problem with fungus, which may mean nothing, as I have only had Canon lenses in the same timeframe.

Like most living things, they have preferences, which may possibly explain why Sigma Lens coatings appear more susceptible to attack than other manufacturers.

Hope that helps.

[Dave_S]

Re: Lens fungus prevention

Maybe its because my observatory is well ventilated, that my telescope optics have never suffered from fungal growth. This despite them being out there in all temperatures and humidity levels.

Either that, or the fungus spores don't like the taste of the lens coatings used.

With Sigma lenses, at least mine, and others that have been reported, the fungus forms on the inside of, and between the lens elements, where it can't be removed without stripping down the lens cell.

As Sigma seems to feature with respect to this problem, Sigma must be aware of it, and yet they seem to choose not to address the issue.

Dave

[colin C]

Re: Lens fungus prevention

As Sigma seems to feature with respect to this problem, Sigma must be aware of it, and yet they seem to choose not to address the issue.

It must be terrible if you are on the receiving end of this and I did early during my photographic career.

However, I do have a little sympathy with Sigma, as they have no direct control over how and where the equipment will be used. Similarly a clutch on a car is generally not covered under warranty unless there is a clear manufacturing fault. I have elderly relatives still driving and I cringe at how much they rev the engine to pull away from a standing start. I have smelt that unmistakable burning clutch lining smell on a number of occasions. I don't think I would ever buy a car from them!

[nickorando]

Re: Lens fungus prevention

The best way to stop fungus is to actually use the lens, especially in higher UV conditions - UV light deactivates the spores even if they do get in the lens. The worst thing you can thus do is keep it indoors, zipped up in a case. That's not a manufacturer issue, it's frankly user error. Use your lenses if you want to keep them fungus-free, and better yet, don't fit a UV filter as a matter of course.

[Dave_S]

Re: Lens fungus prevention

What you say Nick, may well have some relevance, but my astro telescope optics never see the light of day, let alone any sunshine, and yet have never suffered fungal growth. This despite being coated optics, in one case a triplet apochromatic lens cell, and always stored with a lens cap on.

Then again, over the years, something like 50 of them, having always had Canon lenses, which were stored no differently to the way my lenses are stored today, not once did I experience fungal growth. Not until a bought a Sigma lens that is.

Bad luck, or coincidence maybe, but when I read reports of others having fungal growth problems with Sigma lenses, I'm not so sure.

I think its reasonable to pose the question, is the chemical composition of the lens coating used by Sigma, more susceptible to fungal growth, or is the same problem happening with other manufacturers lenses, but people aren't reporting it on the forums etc.

Maybe they are suffering in silence, and only Sigma lens users speak about the problem?

Dave

[Nathaniel]

Re: Lens fungus prevention

I think it is humidity that causes fungus growth. Take the example of cheese kept in the fridge for a week or two unused. Dry air cannot IMHO breed fungus spores.

[digiman]

Re: Lens fungus prevention

I have an Olympus OM10, with a veriety of lenses. There are 2 genuine olympus lenses, which are pristine, and, two third party lenses, both with fungal marks inside the glass. The camera was in storage for many years, in a locked flight case. It was only when I took it out a couple of years ago that I discovered the marks. I guessed maybe it was the grade of coatings that third party manufacturers use on their glass. They need to be competitive so they use cheaper materials.

[colin C]

Re: Lens fungus prevention

They need to be competitive so they use cheaper materials.

Or perhaps the fungus like the taste of them better. :)

[nickorando]

Re: Lens fungus prevention

Without doubt humidity is a problem. Lenses left unattended in cases are at greater risk than those that have air flowing around them or are used in sunlight. Silica gel certainly helps if you have to leave your lenses for any length of time, but the best solution is not to do so.

I find it wildly improbable that any manufacturer's lenses are more prone than others. I've certainly never heard this suggested before, and it has all the hallmarks of a typical internet myth TBH - these things are self-selecting and not likely to be statistically significant. I've had relatively few lenses affected over the years, but none of them have been any of my Sigmas. One I never actually had it on myself, but was bought after the fungus had been removed - a Zeiss Planar. If anyone thinks this has some sort of cheap, defective coating, they're doolally. ;) Of the rest, another was also a Zeiss lens, albeit Carl Zeiss Jena, one was a cheapo Paragon, and the only other one was a Zuiko. I've owned hundreds of lenses.

If I were to hazard a guess as to why some people were reporting Sigmas as being affected, it would be that they're more likely to be sitting unused while people use their marque lenses, TBH.

In terms of preventing fungus, use your lenses, don't lock them away. If you have to store them, keep them with silica gel. Be careful when cleaning - fungus lives on dust, but pushing it into crevices can make the risk worse. If you fit a "protection" filter, take it off regularly and allow air circulation - otherwise it can provide a fertile breeding ground for fungus.

[digiman]

Re: Lens fungus prevention

Or perhaps the fungus like the taste of them better. :)

True! I guess different does'nt always mean cheaper. I have no doubt that the storing of the kit was the problem. I wasn't aware of lens fungus before storing, so I take responsibility for the damage, and wasn't blaming the manufacturer.

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