Some history of fungus research (1 Viewer)

Eleven years ago I was on the Net trying to find out about fungus on optical instruments. I ran across a website that citing research circa WWII and printed a copy - 14 pages, Reviewing it recently, I thought that perhaps some of Bird Forum's more recent members would find this of interest, so the following is the web reference.

http://www.europa.com/~telscope/fungus.txt

John

This is outstanding...though I'm still reading it through.
....
On the fungus topic

I have an old hard leather doctors type suitcase (maybe 50yrs old) which is just perfect for transporting six or seven pairs of binocs, but I'm concerned that it could be infested with fungal spores. It smells fine. I've wiped and vacuumed it out...its felt lined. Been in my wardrobe for ten years....where I also keep some binos...

Can somebody please tell me I'm being silly re my reluctance to use this bag for good binos. All my binos are sealed.

Cheers

I don't think that using it temporarily for transport should cause any problems, even if the leather contains more spores than other bags you would use. The main thing to worry about is the storage. If you live in a rather dry environment (say average humidity below 60-70%) you don't need to bother much. If your region is humid, best keep everything (sealed or not) in a dry box.

dalat said:

I don't think that using it temporarily for transport should cause any problems, even if the leather contains more spores than other bags you would use. The main thing to worry about is the storage. If you live in a rather dry environment (say average humidity below 60-70%) you don't need to bother much. If your region is humid, best keep everything (sealed or not) in a dry box.

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For six months of the year here it is very nasty high humidity with 30c + each day in summer. It's a bit of a worry. I keep the air con on when possible.

I also have a couple of vintage dive watches (not used in water)...one slowly started to condense inside the crystal when in front of aircon, or if I put an ice cube on its crystal. even with its trick crown (winding and setting time), over years it had neutralised with the ambient humidity. I opened it and dried it out on a super dry day...no probs since.

. The Australian troops in World War II, who were I think in Burma or nearby in the jungle, had brand new optics that were destroyed by fungus within less than six weeks. This was a major problem, which had to be tackled urgently.

Personally, I would not use the 50-year-old case. I'm very wary indeed of old cases. Even new ones I smell very carefully to see if there's any sign of fungus or mould.

I had a brand-new China binocular, which had moisture and fungus in it even though it was marked waterproof.

The number of binoculars that I've seen ruined by fungus is enormous.

dalat said:

I don't think that using it temporarily for transport should cause any problems, even if the leather contains more spores than other bags you would use. The main thing to worry about is the storage. If you live in a rather dry environment (say average humidity below 60-70%) you don't need to bother much. If your region is humid, best keep everything (sealed or not) in a dry box.

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I agree. Everywhere I've ever lived, fungal spores are everywhere already. Whether a binocular is ruined by them is determined by how it is stored, that is, by whether the bin and spores are kept in conditions of light and humidity that allow for spore germination. Keep it dry and the spores remain as inert as any other dust.

--AP

Alexis Powell said:

I agree. Everywhere I've ever lived, fungal spores are everywhere already. Whether a binocular is ruined by them is determined by how it is stored, that is, by whether the bin and spores are kept in conditions of light and humidity that allow for spore germination. Keep it dry and the spores remain as inert as any other dust.

--AP

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Porros suck in fungus spores as well as moisture, so even if you store them in a dry place, some moisture might get inside the bin along with fungus and cause it to grow. It will get light when you use the binoculars outside.

Living in a humid valley environment, fungus can pose a threat not only to non-WP binoculars but also to humans. Here's what happened to one of my neighbors who spent a lot of time gardening in her fungus-infested backyard.

fungusamongus

Brock

. Brock, looking at that picture there is not mushroom for doubt.

Fungi love to grow on leather and wood... materials which were prevalent in the construction of older equipment. Older equipment might have even been lubricated with animal-dervied greases/oils.

Japan was an optics leader, even in pre-air-conditioned times. Japan is horribly humid during the summer. Certainly fungi must have an issue in Japanese optics since its inception.

The articles seem to neglect to emphasize that light inhibits fungi growth.

Old Olympus lenses, particularly zooms, are often victims of fungus, as are many others.
In Asia opening up lenses and cleaning fungus is routine. Not done in the U.K.

can fungus attack the exterior of lenses as well, or is it mainly an internal thing as I've seen?

Are water tight binos less prone to fungal damage?

Should an old fungal scarred bino be quarantined from high end glass?

I'm hardly an authority on anything, but from what I have read, fungal spores are microscopic and can exist anywhere, including in the atmosphere when they are assembled. And they can attack exterior glass. Water vapor and temperature evidently are triggers for the spores to multiply. And intriguingly, some research suggests that the possibility of certain kinds of optical class provides "forage" for the spores, while others don't. We must have some scientists reading Bird Forum who can help us fungal neophytes better understand what is happening.
Or perhaps as I shared with a fellow forum follower in a private mail, we can become philosophers and resign ourselves to the thought, that barring unforeseen accidents, etc., etc., the microorganisms are going to get all of us in the end, anyway.

. Fungus can and does attack exterior glass surfaces of lenses, but as these are easily cleaned, one can wipe it off as soon as one sees it.

Waterproof binoculars are generally much less prone to fungal attack, assuming that they have been assembled correctly in the correct conditions to minimise fungus.

I don't know what you mean about the high-end glass, but generally high-end glass is more susceptible to fungal attack than simple glass.

Very old lenses made of basic class types i.e. lenses more than 100 years old are often free of fungus because the glass type is hard and just not susceptible to this type of attack. However, I think even granite might be attacked by fungus. I think that the old softer flint glasses do probably suffer more from fungal attack and also from devitrification, where they become opaque.
For instance, the UK 12 inch Cambridge telescope had to have a new lens made from modern glass because it became unusable. I think this was about 150 years old. The modern objective lens is very good.

I think that the fungus feeds on what leaches out of the glass.

As an aside, I bought two Minolta cameras, old film cameras, and they seemed to have bits of dust in the viewfinder.
I realised that the dust was moving, and it was going round in circles on the Fresnel screen circular depressions. These were some kind of mites. I can't remember if I counted six or eight legs. The size was something like 1 mm, perhaps smaller, but I can't remember. I put both cameras repeatedly in the freezer at -18°C, two days in two days out for about five cycles. But I still was not sure if they were dead dead or just sleeping dead. So I gave the cameras away. Unfortunately I also had the rare 250 mm F/5.6 Minolta mirror lens in the same package. I also gave this away perhaps stupidly as I've seen these going now for £400. I hope my friend realises that he got a good deal as the whole package was free.
I have never bought anything else from this dealer, although I don't know if it is the conditions that he stores things in.

Besides fungus, lenses like the 7 inch F/2.5 Kodak Aero Ektar suffer from star shaped faults from the cemented pairs, where the balsam is failing. It looks, bad but I don't know if it really affects the performance.
More importantly, because two of the internal lenses are thorium glass, they have become brown and they probably act like a T/4 lens rather than T/2.8 or so. They are coated seven element lenses, made for 5" x 5" film. The 12 inch F/2.5 is similar but much larger, made for 9" x 9" film.

Taylor Taylor Hobson lenses and their more modern successors have always been made to be disassembled easily for cleaning. But many lenses need specialists to disassemble, clean and re-assemble. The main problem is then that they are then probably not properly aligned or collimated. For instance I had a Vivitar 600 mm F/8 solid Cat lens that was simply superb. But a secondhand one was awful, as clearly it had been taken apart and reassembled. And I've seen many other similar cases. Even so-called professional repairers do not have the facilities to perfectly align lenses. If one finds an essentially perfect lens, it is best to leave it alone unless it is really bad.

With binoculars, those who are able should clean off the fungus and also the film of moisture that forms on the surfaces, as besides anything else the transmission becomes low.

If I see fungus in an optical item I generally avoided it like the plague, as I am not able to repair it myself, although I have done with large aircraft lenses in the past. My mantra is that the fungus will not get better. It might stay the same but probably will get worse. Although it could be that the marks are the result of fungus that has been cleaned off and there is no active fungus any more attacking the glass.

The fact is that not all glasses are attacked by fungus, as there are glass items centuries old, which are still good. But modern glasses are often exotic, and only survive because the coatings are so hard and properly applied. In fact with the best lenses, many have to be coated immediately they are made, as they tarnish almost instantly. There is a lot that goes on in lens making, which the average user doesn't realise.

Rathaus, I realise what you mean now.

It would make sense to keep any optical item, which has fungus in it away from clean optics, although I don't know if in fact the active spores would migrate to the good equipment. Personally, I keep them separate.

Regarding the previous post. The coatings also get eaten by fungus as well as the glass. And I suppose that the fungal spores can exist on the metal parts as well and also on any grease.

. My friend and I have discussed the matter fungus many times and papers have been written, but it is such a can of worms it hasn't really been seen in print.

The following contains errors, and I will be happy to be corrected.

Fungus produces extremely small spores, almost like bacteria. Fungus that falls on glass contains spores, which can be dormant for a very long time. They are mainly waiting for moisture so that they can try to germinate. If they succeed they produce mycelium, tiny long threads.

They usually fail on clean glass, particularly glass which is dry.

The fungus have a package with them, like seeds, which contain food. They have capital and they can try to form a new empire.

. Dirt is food for them. Such as particles of skin or grease from fingers.

Glass supplies nutrients, particularly soft glass. And the acid deposit etches into the glass.

. The whole process is a bit like propagation of plants.

Sodium glass is good. Potassium is less often found. The air supplies nitrogen.

Phosphate glass is bad. And these were soon normally discarded.

Fungus can form on some hard glasses, but the fungus is unable to corrode the glass, so it fails to etch into the glass, and can just be wiped off.

Between 1920 and 1940 borate glass had lead introduced in bigger quantities to produce glasses with higher refractive indices.

In a way, the whole process is similar to farmers who use fertilisers. NPK.

So basically, whether the glass is etched by fungus, depends on the glass type primarily, and then the conditions.
It is moisture, basically, and relative humidity. Which is dependent on temperature.

Although old glass in windows seems to have survived perhaps hundreds of years, it is not as good as one thinks, as it has been subject to sandblasting. The coloured windows have metal in them.

Basically by trial and error optical glass has developed, with pitfalls on the way, where certain glasses were found to be inappropriate.

I hope that at least some of this is useful.

. Further to the last post 15.

My friend thinks that in World War II in the jungle things like binoculars failed in as little as two weeks from new. Not the six weeks that I've seen.
The whole binocular would have mushrooms and fungi growing on it, not just the glass. Various methods were tried which were partly successful, but this was a continuous problem.

You're right about spores being everywhere and the issue being the
conditions..it's just like fungus and houses, there is a temperature/humidity chart box
where things grow.

Some experiences:

Most of the Navy Wollensak WW2 6x30s I got had fungus.
It cleaned up easily, but the centerlines of the core 'veins' in the formation left tiny tracks etched.
So...in that case, most of the fungus didn't etch but a skeletal track was etched in the coating.
I stopped getting those, mainly because the salt corrosion and tricky assembly made work hard,
and because about half had something chipped. Looks like life at sea is very tough.

I restored Bushnell Customs and Custom Compacts that looked like they had been dropped
in the dirt for a few seasons...forgotten by an old owner? water crust, mold, fine dirt.
But....cleaned up with BonAmi (gently), and no harm to the coating. I credit Fujinon for
some extra durability.

Assorted other binoculars with light lacy fungus have cleaned up with no coating loss,
or a loss of just a 'dot' at the center of a lace web. Bullseye fungus...similar, just a little dot.
Windex usually works, Bon Ami for a hard case, with my thumbpads.

I throw out 95% of the leather cases. they fall apart quicker so they make the binocs look bad,
they may release old spores as dust, and they are never polished like they should be so the
oxidation guarantees crumbling. A good case I will polish with boot-polish and a little Wd40,
wiping off the excess with paper towel and taking away dust. Leather cases should be polished
when they come home. They can't be in the factory....too soon.

OPTIC_NUT said:

You're right about spores being everywhere
Most of the Navy Wollensak WW2 6x30s I got had fungus.
Looks like life at sea is very tough.

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As far as I know during WW II the Wollensak 6x30 was solely a US Army binocular called the M5 and designated for use only by Britain under Lend Lease. Does yours have Navy markings?

I got several pair of Wollensaks where the local sellers said
they were owned by a Grandpa in the Merchant Marine.
I suppose that's where I formed the presumption of the Navy.
Not quite the same. Maybe they used lend-lease binocs.
Given the history of the Merchant Marine, I suppose a lot of
them may be at the bottom of the sea now.

. One might think that hard coatings would protect any type of glass from fungal attack. This is partly true.
However, if the coating is scratched then the process of etching the glass underneath can begin.

But more often, the failure I think is at the edge of the glass element. This may or may not be blackened, but I don't think that the edge has the hard coating that the front and rear surface of the lens element has.

I recently got a Minolta 70 to 210 mm F/4 classic lens, possibly circa 1990. Although I asked the salesman to carefully check for fungus, when I got it and shined a torch into the front of the lens I immediately saw that at the edge of the front element on the inside, there was an area of fungus. In addition, with the rear zoom group, the front element again had an area of fungus at the edge on the inside surface. So here two of the lens elements were affected by fungus, which seems to have got in from the edge of the glass element. This must have worked its way into the glass, rather than into the coating.

I just received a replacement lens, which is beautifully clean and has excellent multi coating. Minolta were very early into multi coating as far as Japanese lenses are concerned.

The best lenses, have edge blackening applied in two layers and baked. And each lens element edge has its own tuned blackening material, which depends on the refractive index of the individual lens elements. These lenses cost about £10,000 each.

As to Minolta binoculars, it is a great shame that the Minolta Standard extra wide-angle binoculars only have basic coatings. The later Activa binocular, such as the 12 x 50 has multi-coatings on every surface and very high transmission, as shown by the very faint stars that are seen using it.