Fungus risk in vintage Leica lenses – how likely is it really?

[Atr3ju]

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Hi everyone,

I'm the lucky owner of an old 1932 Elmar 5cm lens and wanted to ask about your experiences with fungus in old lenses, especially if you live in a temperate region like Switzerland.

Switzerland isn’t especially humid overall, but I do wonder how likely it is to get fungus in older Leica lenses – particularly those that have been stored for decades. Some of these were stored in camera bags, old leather cases, or drawers – sometimes for years.

How common is fungus in these old Leica lenses?

Is the Swiss climate generally safe from fungus, or should I still be concerned?

How do you store your vintage gear to prevent fungal growth?

I know that proper ventilation and low humidity are key, but I’d love to hear from other Leica users who live in similar climates or have dealt with this issue.

Thanks in advance for sharing your insights!

[spydrxx]

I'm in the Chicago area, humid in summer, not so in winter. None of my Leica lenses, mostly vintage over 50 years old, most purchased used, none have signs of fungus. I merely keep them all on a shelf exposed to ventilation, never store them in leather cases. So, to respond to your question...Leica lenses are no more susceptible to fungus than any other lenses. Older lenses stored in humid regions often to get fungus, as do lenses improperly stored. If your Elmar doesn't have fungus, I wouldn't worry about it. 

[SpotmaticSP]

I'm living in The Netherlands and I do literally nothing against fungus; I just treat my stuff well. That means - using everything every now and then. Get out that camera, trip that shutter! Focus that lens! Stop down the diaphragm! Also remember to avoid temperature shocks. Don't bring a stone cold camera in a damp environment, such as a crowded Cafe. Allow the camera some time to acclimatize itself! So upon coming home - get it out of the case and let it gradually warm up.

At least this is what works for me. Fungus will not grow in lenses that are used every now and then, and when treated well. 

[jaapv]

Fungus spores are everywhere in the air around you and may land on your lens at any time, virtually always without any negative effect; 99.999% of the time they prefer cheese and old fruit over your lenses. If you are in a moderate climate there is little to worry about. Look at the lens from time to time - if it gets a bit hazy or has a few spots that you don't like, just give it a CLA and it will be fine again. Fungus needs quite some time to eat into the coating - it does not happen overnight. Moist tropical climates are different, everything grows at an amazing rate, but I have a sneaking suspicion that Switzerland does not quite fit into the tropical and moist category. 

[pgk]

Fungus is an interesting problem in lenses. I have a lot of old lenses some dating back to the 1860s. Few suffer from fungus. I have not looked formally into the subject but I am aware that many lenses suffereing from fungus are actually relatively recent and I suspet that coated lenses are more susceptible and that etching is more prevalent on the coating. I'm sure that there will be many who will say otherwise but my arguments are as follow:

Lenses which are uncoated and made from older glass (which may contain relatively poisonous somponents such as lead (crown glass)) offer little of interest to fungal spores, and may actually deter them, so don't suffer from fungus to the extent that later lenses do.

Later lenses with one or multiple coatings which are less likely to be poisonous and may have material in them of more use to fungus are much more likely to suffer from fungus if stored in darky, damp, warm conditions. Damp is the prerequisite.

To prevent fungus lenses simply need to be stored in dry conditions which are not conducive to fungal spores developing. I use small packs of silica gel which are checked and changed regularly. I do have some lenses which have fungus; all were already affected by fungus before I got them because they have been stored in damp conditions. On plain glass lenses the fungus has always wiped away and in the case of the lenses I have does not seem to have caused etching which apparently is caused by some fungi secreting acid which damages the surface that the fungus is on. Coated lenses seem to suffer more but I'm not sure that any of the ones I own have etching in the coating even so. My guess is that dirty lenses (mucky glass surfaces) stored in damp conditions are most lkkely to be affected simply because they offer fungus potential food and appropriate conditions.

Be aware though that some other lens conditions such as separation can look a little like fungus but aren't.

[zeitz]

I have found that Canon rangefinder lenses are more prone to fungus than Leica rangefinder lenses.  Also certain achromat (cemented doublet) lenses from the 1950's seem prone to fungus.  These include lenses from Astro Berlin, Kilfitt and Tewe, but not from Novoflex.  

I have never seen a complete explanation of fungus on optics.  Hydrogen peroxide is often used to clean fungus from optics.  Hydrogen peroxide is water (H2O) with an extra oxygen (H2O2).  The explanation from a doctor who uses hydrogen peroxide to treat some human fungus is that fungus can be anaerobic and that the extra oxygen kills the anaerobic fungus.

So keep glass clean and dry, don't store glass in boxes or leather, use desiccants, and examine the glass regularly.  Get the lens cleaned when fungus effects are first observed.

[250swb]

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Why are you all talking about storing a lens! Use it, UV light kills fungus!

 

[pgk]

54 minutes ago, 250swb said:

Why are you all talking about storing a lens! Use it, UV light kills fungus!

Yes, but. I had a 35/2 v.4 with separation in the rear group. I was able to get this recemented via an optical firm (don't ask, no they won't do this again), and the comment which came back was that the cement which was UV cured required a very high dose of UV because the glass was highly UV absorbent. So using sunlight might work but it might take a long time, if that is, the intensity within a lens ever builds up sufficiently to kill fungus. Prevention by keeping lenses dry is better than having to cure them.

[SpotmaticSP]

5 hours ago, zeitz said:

I have found that Canon rangefinder lenses are more prone to fungus than Leica rangefinder lenses. 

Did you buy them from Japan? 😉

Japan has a very damp climate. That's why many lenses sold on auctions in Japan have fungus in them, or were recently cleaned from fungus. 

[250swb]

9 minutes ago, pgk said:

Yes, but. I had a 35/2 v.4 with separation in the rear group. I was able to get this recemented via an optical firm (don't ask, no they won't do this again), and the comment which came back was that the cement which was UV cured required a very high dose of UV because the glass was highly UV absorbent. So using sunlight might work but it might take a long time, if that is, the intensity within a lens ever builds up sufficiently to kill fungus. Prevention by keeping lenses dry is better than having to cure them.

How do you keep them dry in Scotland 😁

Yes of course, I don't have all my lenses lined up on the windowsill bathing in UV, they are all in drawers with bags of silica gel. But in average European climes I wonder if fungus was ever a worrying problem when people had fewer lenses and used them all the time. It's relatively recently when Dad's old film camera and photo gear get put into cardboard boxes and stored in the damp garage that fungus became the thing to look for as they emerge onto the market. But inactivity in storage isn't the only problem for old lenses, without an airing they are more likely to gas out and cloud the lens when the old grease stops being circulated. I've had a Canon 50mm Serenar do it, the inner glass surfaces were totally white, but fortunately with that lens it's a simple fix.

 

[pgk]

30 minutes ago, 250swb said:

How do you keep them dry in Scotland 😁

But in average European climes I wonder if fungus was ever a worrying problem when people had fewer lenses and used them all the time.

In Pelicases with indicator silica gel - when not in use of course. Same as in North Wales where the climate is very similar.

Yes, you are spot on. I reckon the best way of avoiding fungus is to use lenses, and dry them if they get damp and generally look after them. And not worry about something that probably won't happen if you do use and look after lenses! Oddly enough I've never come across a photographer having problems with fungus in lenses which are in constant use. Stored lenses on the other hand, if not kept dry, can be infested; seen this too.

[jaapv]

1 hour ago, 250swb said:

How do you keep them dry in Scotland 😁

Yes of course, I don't have all my lenses lined up on the windowsill bathing in UV, they are all in drawers with bags of silica gel. But in average European climes I wonder if fungus was ever a worrying problem when people had fewer lenses and used them all the time. It's relatively recently when Dad's old film camera and photo gear get put into cardboard boxes and stored in the damp garage that fungus became the thing to look for as they emerge onto the market. But inactivity in storage isn't the only problem for old lenses, without an airing they are more likely to gas out and cloud the lens when the old grease stops being circulated. I've had a Canon 50mm Serenar do it, the inner glass surfaces were totally white, but fortunately with that lens it's a simple fix.

 

How do you keep them warm in Scotland? 

[zeitz]

3 hours ago, SpotmaticSP said:

Did you buy them from Japan?

Mostly purchased in the US.  But it is impossible to know the previous ownership of the lenses.  In contrast, while I don't have many Nikkor S rangefinder lenses, I have never seen a Nikkor S lens with fungus.  I have bought and cleaned Nikkor Ai lenses with fungus.

[SpotmaticSP]

5 hours ago, zeitz said:

Mostly purchased in the US.  But it is impossible to know the previous ownership of the lenses.  In contrast, while I don't have many Nikkor S rangefinder lenses, I have never seen a Nikkor S lens with fungus.  I have bought and cleaned Nikkor Ai lenses with fungus.

I think in the US the houses are not very well built. Lots of wood and dry walls. Damp basements. Unless you buy from Arizona or states like that. 😉

[roydonian]

7 hours ago, jaapv said:

How do you keep them warm in Scotland? 

I managed it by moving to Southern England around 60 years ago. I can remember writing home and expressing amazement that I'd been in England for five weeks without seeing rain.

[Kl@usW.]

A short summary: https://www.zeiss.com/consumer-products/us/service/content/fungus-on-lenses.html