When newfound small dust and debris in M lenses might become host for fungus?

[cwatgo1970]

I would think most members in the RF forum have encountered more than their fair share in discovery of dust and small debris in lenses in the past. As most know dust is a fact of life in the lens world which many of us learn to live with. I'm one who normally wouldntt sweat dust matters, but in the past I've observed where some dust and small debris fragments which I had allowed to remain in a lens had become the starting point for small fungus growth years later. Recently, I noticed the presence of a very small debris fragment inside my 90mm Elmar which I had not noticed before and now worry about the possibility of it maybe generating fungus growth in the future. My questions are, how many of you fear or have experienced such particles turning host for fungus growth? And what degree do some of you feel the presence of dust and small debris in a lens should be a concern and warrant a CLA?

 

[icebear]

Just keep the lenses open, dry and well ventilated when not in use. NOT in any type of closed container whatsoever - worst possible option : plastic bag.
Fungus will only grow under humid conditions - if you avoid these there'll be no fungus, no matter if there are any particles around inside your lenses or not.

 

[hans voralberg]

Quite a lot of dust in my 194x Summar and still no fungus, same for all my lens in my sig, which are mostly 40 yo.

 

[SolaresLarrave]

Dry and cool place is the solution. Dust sometimes moves around, and if I remember clearly, if it's unorganic it won't generate fungus at all.

Just use them. Don't worry about things that may or may not happen.

 

[Al Kaplan]

Like icebear said "out in the open". Fungus grows best in the dark with no air circulation. Leave your lenses uncased, no caps, where light can get to them. You can always blow off a little dust. When you head out to use them you can carry them in cases to protect the ones not on a camera at that moment.

It seems that older lenses that had the elements glued together with Canada balsam, which is organic, had a much greater tendancy to develop fungus than more recent lenses. I believe they've been using a synthetic substance for the past couple of decades.

There really doesn't seem like there's any rhyme nor reason why some lenses end up getting fungus while others don't. I've got some lenses over fifty years old that are clean as a whistle. My LTM 85/2 Nikkor, at least fifty years old, had a tiny bit in one place on the edge when I bought it over thirty years ago. Since I've owned it it's been mostly on a camera with no front cap and only protected by a lens shade. The fungus hasn't gotten any worse. A couple of years ago I bought a bunch of misc. photo equipment at an estate sale. Only one lens had fungus, a fairly recent 200/4 Micro-Nikkor. It's really a crap shoot.