Fungus

[Torquinian]

I wonder why it is that classic camera dealers nearly always manage to find fungus in a lens when they are buying and knock the price down, or want a fortune for having it cleaned. I have had this happen several times when the lens looked perfectly clear to me and took good sharp photos. Maybe I am getting paranoid thinking that they find fungus to make their fortunes.
If the lens has always been kept with front and rear caps on in a dry place, how would it get in there.

[beejaybee]

There are lots of lenses with internal dust, which is not necessarily an issue. I think some people will point out a bit of dust contamination & scream fungus, especially if they have an interest in knocking the price down. A few really do have fungus, those that do have it do need attention if they're ever to be useful in the future.

If the lens has always been kept with front and rear caps on in a dry place, how would it get in there.

Many lenses have gaps in the focusing or zoom mechanism which can suck dust particles in. Fungal spores are a very small fraction of "normal" dust. If they get in and there is food available (possibly pollen grains) plus dampness, the fungus can grow. The issue here is that growing fungus can eat into the coatings on the lens, so just dismantling and cleaning isn't going to fix the issue.

[nimbus]

The f-word!

The thought of it makes me shudder. I always check used lenses for fungus, I've found a number suffering from it, there is the fear that it could spread to others. In one case the lens actually smelt musty and had a particularly fine crop inside, the seller (at a camera fair) tried to say it was only dust and would clean out.

[Roger_Provins]

I find fungus it quite a few second-hand lenses more than ten years old - probably about a third of those I examine. Use a torch to shine in both the front and rear and it will show up stuff that's not seen without.

[Torquinian]

This seems to be a recent discovery. Ten years ago I had never heard of funfus in lenses.

[Roger_Provins]

This seems to be a recent discovery. Ten years ago I had never heard of funfus in lenses.

You may not have but it's always been with us. I've been cleaning it off lenses (when possible) for at least the last 40 years.

[Bob Maddison]

I own a small telescope made in Germany in 1935 which has a beautiful floral growth inside the objective lens. This has been there since I first owned it ~25 years ago. The growth can only be seen by looking at the front of the 'scope from a slight angle. It looks rather like the start of a frost pattern on a window. Nevertheless, the definition of that 'scope is second to none.

Leave well alone unless you really prepared to spend some money.

A camera lens isn't sealed, otherwise it could be difficult to focus! This means that temperature changes inevitably cause some moist air to be drawn inside the lens which might, or might not, be seen as condensation. This is an ideal breeding ground for fungi and certain bacteria whose spores are drawn in with the moist air. The only way to prevent this is to avoid temperature changes and to keep the lens in an airtight container.

Above all, don't ever attach the lens to a camera and attempt to use it to take photographs: that is certain to lead to a fungal growth within the lens. On the other hand . . . . !

[willie45]

I had a dealer tell me that two lenses I was selling had to have a lesser price tag due to fungus. I was pretty surprised as they weren't old at all. I was told that depending on storage conditions etc etc this wasn't uncommon. As these were on a commission sale I thought it wasn't in his interests to sell for lower so believed him.

As an aside, are there not "anti-fungal" lens cases? I'm sure I've seen some advertised on sites?

Willie

[AGW]

The fungus is able to metabolise the coating and as a side effect etch into the glass. I would be really impressed if the fugus could free up enough energy to sporulate. I have never seen any ID of the species involved, but I have always assumed that it was one of the lichen forming species- they are able to establish on dry bare rock, incredibly harsh conditions for life.

Graeme

[Torquinian]

I had a dealer tell me that two lenses I was selling had to have a lesser price tag due to fungus. I was pretty surprised as they weren't old at all. I was told that depending on storage conditions etc etc this wasn't uncommon. As these were on a commission sale I thought it wasn't in his interests to sell for lower so believed him.

As an aside, are there not "anti-fungal" lens cases? I'm sure I've seen some advertised on sites?

Willie

That is exactly what happened with me and why I started this thread. As well as their sales commission they wanted £125 for cleaning out the "fungus".

[willie45]

That is exactly what happened with me and why I started this thread. As well as their sales commission they wanted £125 for cleaning out the "fungus".

Ah! The dealer told me there was fungus but nothing affecting image quality and didn't ask me to fund any cleaning. I was surprised because the lenses weren't by any means old.

There is an article here which might be of interest to some

http://www.chem.helsinki.fi/~toomas/photo/fungus/

I can't find out anything about these lens containers I remember. They were plastic units which screwed shut and had a holding area for silica gel at the bottom. IIRC they were only made for Canon and Nikon lenses and came in two sizes? I might be wrong.

Willie

[Torquinian]

Thanks;- that article by Toomas Tamm was very interesting.

[willie45]

I worried for a bit after reading it. It's the doomsday scenario for your lenses and there's precious little you can do apparently

Willie

[Torquinian]

If you are not told it is there I bet you would not see any effect on your photographs and wouldn't worry..
The lenses that I was told had it were giving perfect results.

[willie45]

I reckon you're right. As I say I did worry for a bit but then adopted a philiosophical attitude

Willie