View Full Version : lens/fungus/mold

Raven Garrow
3-Jan-2001, 21:57
Hi, I had left a lens in my car on a cold winter night maybe for an hour, and when I brought it in the house, the lens elements fogged. It went away, but I was won dering if this is the way lenses get mold of fungus? If so, then what does one d o when trekking out on those cold days, then entering into a warm environment.?

4-Jan-2001, 00:33
One answer is to leave your equipment in the car (when not in use) - I do that for weeks at a time in the winter, then you don't have to worry about rapid changes in temperature. Another is to enclose the lens in a "zip-loc" bag - don't worry about squeezing all of the air out, the relative humidity is so low that whatever air is inside the bag is drier than the air inside your house. The trick is to leave your equipment in an insulated container so that it warms up slowly, it's the temperature differential that causes condensation to form on cold objects. A foam-padded camera bag will do. I bought some large collapsable "coolers" that work great. "Fungus" is all around us and probably in almost all lenses of any age. It requires darkness and moisture to grow - eliminate one condition (preferably both) and you'll never have a problem.

Bill Jefferson
4-Jan-2001, 06:57
Hi Raven,

Lens fungus as i undersutand comes form bacteria eating the cement in between the element groups, as the earlier cement was sap from cedar trees, the fungus can be killed by exposure to ultravilot light. Bill

Pete Andrews
4-Jan-2001, 07:03
Condensation doesn't help, but I don't believe that condensation alone will cause a fungal attack on your lenses.After bitter experience, it's now my firm belief that the lens fungus migrates from nearby surfaces that have the right conditions to nurture the spores in their early stages. Prime suspect in my book is leather. Leather lens cases, camera cases, lens pouches, get rid of 'em. They may be hard-wearing, and look and feel a lot nicer than PVC coated mand-made composites, but IMHO leather is an ideal breeding ground for fungus, especially if it has a nice velveteen lining to it as well.

I only have circumstantial evidence to back up this rant, but all I can tell you is that since I weeded any leather cases out of my collection the incidence of fungal attack on my lenses has dropped to zero. Before I did this, I had to be constantly vigilent to catch the first signs of those nasty little cobwebs creeping across the edges of my precious glassware.

4-Jan-2001, 20:03

Lens fungus as i undersutand comes form bacteria eating the cement in between the element groups, as the earlier cement was sap from cedar trees, the fungus can be killed by exposure to ultravilot light. Bill

Don't think so. Fungi belong to a different kingdom than bacteria. They are everywhere. To get them to grow, you need some moisture [although members of some species of Aspergillus can grow at desert humidities] and an energy source. That energy source can be quite variable. Some grow on solder flux and cause problems in industrial plumbing. Some grow on jet fuel and cause problem in airplanes. Some grow on roofing material and cause shingles to fall apart. In lenses, it is usually accumulated oil of some kind. Since many produce organic acids as a by-product, they can etch the lens. By the way, many of the offending fungi are quite resistant to UV irradiation. Particularly the genus Aspergillus which is very common.

So it goes. Enough Mycology.


Bruce M. Herman
5-Jan-2001, 02:54

My lenses have fogged numerous times, usually during the winter when I inadvertantly breath on them, or when moisture from the bellows condenses on the rear cell. They've developed neither fungus, mold, nor mildew, and I don't spray them with Lysol or Tilex. Just put them some place dry for awhile so that the moisture has ample time to evaporate.


18-Oct-2005, 10:27
The websites and forums on building science have tons of information about mold formation and prevention. It boils down to some simple principles:

Mold spores are everywhere all the time. It's impossible to eleminate them outside a sanitized clean room.

Mold lives on anything organic at microscopic levels, so their food is available to them everywhere all the time. It's impossible to eliminate it outside a clean room.

Mold spores germinate when they are allowed to have 70 percent relative humidity for an unbroken 24-hour span. If you deny them either, the spores won't germinate.

Most anti-fungus recommendations involve trying to reduce the moisture content in the volume of air in an airtight container, generally the use of a dissicant. This is very labor-intensive, may be unneccessary, and can even be counter-productive.

Unnecessary? If your equipment is or can be kept in an air-conditioned environment for 6-8 hours a day, you may not have to worry about fungus unless you do something counter-productive. Small hygrometers cost only a few dollars/euros/quid at home or hardware stores. You may find that your living area is already maintained below 70 percent humidity. A hygrometer check of various locations will also show that some spots in a room are more humid than others--the corners of a room close to the floor, for instance, will be more humid than the center of the room.

If your living area is normally kept below 70 percent humidity by air conditioning, it is counter-productive to keep equipment in a container that restricts airflow (especially if it will keep the equipment trapped with un-conditioned outside air).

If your living area is not conditioned and subject to high humidity, it's hard to reduce relative humidity in a small enclosure by reducing the moisture in the air. You'd have to keep the container air tight. You'd have to use the right amount of dissicant to remove the correct volume of moisture. You'd have to periodically refresh the dissicant by heating it. If you make any mistakes, you'll be storing your equipment in a humidor--inviting fungus to dinner.

On the other hand, it's easy to reduce relative humidity in a small enclosure by raising its air temperature just a few degrees. You can buy cabinets designed for that purpose: "Dry safes" are often used by gun owners. They are ventilated containers with low-power heating elements that keep the internal air just a few degrees warmer than the outside air. It's not necessary or even desireable to have an airtight enclosure.

When I lived in Okinawa and the Philippines 20 years ago, I commandeered a kitchen cabinet for my equipment. I mounted a 30-watt light bulb in the bottom part and kept my equipment on the shelves covered with light cloths to keep off dust. Six to eight hours a day does it. I never had fungus problems, even though during monsoon season it was so humid that we had mildew on the living room walls.

To this date, even with air conditioning, I never store equipment in snug enclosures, but always on shelves and covered with a light cloth to keep off dust.

18-Oct-2005, 16:26
I have a theory that lenses made in the Orient are prone to fungi infestation. Oh, and Minnesota - to be fair.

What kind of food does fungi find inside a lens? That scares me more than the fungi.

Anywho, Fungi are heterotrophic. Shamefull behavior, I tell you. It's hard to be Green if you are a Heterotrophicphobe.

from MinneSnowta,

emo supremo
29-Mar-2009, 04:35
I kept my equipment in a medium sized safe with disasterous results: mold.
It occurs to me that if I were a lens engineer i would choose the cement holding the elements together by its refractive index. For example, if I wished light to continue on a straight path I would match the cement to the glass RI. Alternatively, if I wanted it to deviate (analogous to the fish in the water; it's not where your eyes see it) the light is bent by the diff in RI.
Now as I recall, isn't cedar oil (mentioned in this thread) used in microbiology (well it used to be) labs to mount specimens betwixt GLASS slides and GLASS coverslips? In addition to its acting like cement, it had a useful RI.
What implication (if any; I speculating out loud) does this have for 'vintage' lenses and their susceptability to mold?
PS. First: Warm=exapand. Cold=contract. Variation acts like a 'pump' sucking contamination into microcracks. Second: moisture rises to the top of a 70 foot tree (that's a lot of energy to carry fireplace logs to the top of an oak) because of surface tension. Moral: unless moisture is equilibrated between the inside or outside of a crevis/crack/seal of a lens moisture (spores) will come in the screen door.

Peter K
29-Mar-2009, 06:03
Now as I recall, isn't cedar oil (mentioned in this thread) used in microbiology (well it used to be) labs to mount specimens betwixt GLASS slides and GLASS coverslips? In addition to its acting like cement, it had a useful RI.
Cedar oil was used as immersion oil in microscopy. With this oil there is no refractive index jump between the specimen, the coverslip, and the front lens of the microscope.

For mounting the specimen canada balsam was used. The same resin used for mounting lenses.

The problem with this nature products isn't fungus but both can change RI, diffraction and color, depending on air humidity, dilution and age. So today only synthetic immersion oil and mouting cement are used.

But also lenses mounted with synthetic cement can get fungus, on the surface of the lenses too. So canada balsman isn't the problem but storage in the wrong enviroment.

Peter K

29-Mar-2009, 08:47
Interesting thread. I have a problem with threadlike organisms frowing in dilute selenium toner. Anyone have a clue as to the selenium-philic organism.

Peter De Smidt
29-Mar-2009, 09:17
I agree that the biggest problem is humid air/moisture. When your lenses are cold, put them in ziplock bags. Get as much of the air out as possible and then bring them inside. Take the lenses out once they've gotten to room temperature. Store them in an open area if you have air conditioning. If not, plastic boxes with sealed lids work well. Just be sure to add a bit of desiccant in the box. Don't store lenses in your basement. In particular, don't leave enlarging lenses on the enlarger, if that's in the basement. I lost the only enlarging lens that I bought new to fungus by doing that.

John Bowen
29-Mar-2009, 13:39
I kept my equipment in a medium sized safe with disasterous results: mold.

Emo...you must be cursed! First the misrepresented Deardorf on Ebay, then a bellows falls apart from your cleaning method and now lens mold. No one deserves that much grief!

1-Apr-2009, 13:31
I've had a whole slew of bad luck with mf and lf equipment. Not just ebay either, supposedly perfect lens and camera with a fungal bloom on the front element (oh well, good deal still on the camera). A Hassy outfit that looked like it was put together out of the bad pieces from a old pro's kit (8+?!?, at least I got a refund). Now I just got a Ysarex with the worst fungus I've seen in a supposedly usable lens, seller wants me to send a picture of it and implies its probably dust or something.... sigh... at least it was cheap but almost so cheap its hardly worth the lost shipping.

Why is it that seller's don't see this stuff when they sell their junk?
Am I just being overly picky, should I now expect that old glass is going to have etching on it?
I never had this sort of grief a decade ago before I got out of photography for a while. Has all this equipment just been rotting in people's basements since then?

Peter De Smidt
6-Apr-2009, 16:14
No, you're not being overly picky. I too have bought "excellent" lenses on Ebay which turned out to have obvious fungus. My guess is people don't know what to look for, and they don't realize what a problem it can be.