the cornucopia

fungus and photographic equipment - the facts


This article was written in response to many enquiries from Olympus Circle members about the risks posed to photographic equipment by poor storage, damp conditions, humid atmospheres and any recommendations as to reducing the risks or remedying any fungus caused problems.


While every effort has been made to reflect the current levels of understanding, the writer, and the Executive Committee assume no responsibility for the content and accuracy of, or efficacy of treatments contained in the following.


It is imperative to understand that while many problems occurring inside lenses can be repaired others cannot and might result in the destruction of the lens. Prevention is better than cure and by applying some basic rules you can avoid the problem altogether. These rules might seem insultingly simple but we all make mistakes.

  • 1. Always dry out your gear when coming in from wet, damp, very cold or humid conditions. Place near a source of dry heat – radiator or boiler – do not use the airing cupboard.

  • 2. Unless absolutely certain that cases are 100% dry don’t keep your gear in them. If cases are genuine leather do not store in these - even if dry. Store leather cases away from your equipment.

  • 3. Keep your equipment free from dust and finger marks – use a high quality brush, lens cloth and a can of compressed air – regularly.

  • 4. Use your equipment regularly – exposure to dry air and sunlight is beneficial.

  • 5. Ensure adequate ventilation in the room, part room or cabinets where you store or display your equipment/collection.

  • 6. Lower the humidity by increasing ventilation and adding dry heat.

  • 7. Use a de-humidifier carefully as too much dryness can damage equipment.

  • 8. If you have a major problem, consider using “dry” cabinets or air-less bags.

  • 9. Examine all your equipment/collection regularly. Isolate any suspicious finds.


How do we know if our equipment is infected? We must examine our lenses regularly by shining a light source through them and looking for oddities on the various element surfaces seen. Pay particular attention to areas of glass near the outer edge of the lens, near the metal barrel or element carrier. Repeat this from both ends of the lens. Look for oddities that detract from the lens’ normal pristine appearance. Theses oddities can range from a light ‘haze’ to a heavy glaze, dust in various amounts, white sugary spots to heavy brown/grey blobs, or a few tendrils of spidery web to white fuzz. If you see any oddities isolate the item until the problem is resolved.


  • Haze: Normally affects the whole element or in graduation from inner to outer. Can be very slight to very dense, but is essentially an even build up of distilled chemicals or ‘oil haze’. In older equipment this can be a major problem rendering lenses virtually opaque - especially where shutters are between lens elements. Cause: Evaporation of oil based lubricants and other chemicals used in lens (and shutter) construction. Excessive heat can drive out the volatiles from lubricants and these condense on glass elements. Wrong lubricants applied in DIY repairs can exacerbate the problem. Prognosis: Good; see below.

  • Dust: Just as dust deposits itself throughout the house so it can do the same in your lens. Symptoms range from a few white specks to total coverage. It can normally be ascertained by tapping the lens to see if the dust spots move. Look for obvious causes such as deteriorating lens cases or pouches, or boxes that have no ‘sealed’ paper lining – that is the inside of the box is ordinary paper – with rubbing causes dust. Prognosis: Good; see below.

  • White spots: These look worse when the light source is shone through the lens and consists of random white or opaque spots with vague outlines, difficult to focus on, appearing to be deep in the lens, not on the surface of a particular element. Between these spots are areas of perfect lens or areas of opaqueness but no areas of fuzz or different colours. Sometimes described as sugary spots, like small clearish pimples in the lens. Difficult to describe but almost unmistakeable. Cause: Probable balsam failure. Balsam is the glue used to cement elements together particularly in older lenses. Due to many factors it can break down and as it is sandwiched between two pieces of glass its failure is seen as a white spot of lost adhesion or crystallisation. Balsam failure is confined to earlier lenses; lenses made after the early 80’s use man-made cements/adhesives. Prognosis: Poor to fatal; see below.

  • Coloured blobs: In varying sizes from pinhead to ink-spot and coloured from grey to brown to greyish-green. Random in size and place, a little like lichen growth on stones. Cause: Fungus Prognosis: Poor to fatal; see below.

  • Tendrils and webs: In early stages these are very difficult to spot. A few tendrils of fungus can be almost invisible but look carefully for any ‘mother’ growth that may be lurking under a seam or in a metal fold. As this develops it becomes more easily seen and resembles a close-knit spidery web with a concentrated mass from which the tendrils stretch. Cause: Fungus Prognosis: Good to fair [can be fatal]; depends on quick diagnosis.


    Caution: Unless you are particularly well gifted or experienced a DIY solution is NOT recommended. In any case always seek the advice of a professional repairer. If you are confident in your skills you need both the knowledge and the correct tools; we have all refused to buy lenses with obvious marks of bodged entry. If you insist on undertaking such work and use the chemicals referred to later you must be responsible for your own safety and the risk of damage to your equipment.

    Some of the treatments outlined are very easy to undertake – the difficult part is disassembly and re-building the lens components – be warned.

  • HAZE

    This is relatively easy to remove. A lens can be cleaned of these contaminants using a cleaning solution of 50:50 hydrogen peroxide and household ammonia. Other solvents might be considered and as the haze is primarily oil vapour, denatured alcohol or lighter fluid may remove it, but these might also damage any coatings present. Use only the very softest cloths for removal and subsequent light polishing. Dry all components thoroughly before reassembly.

  • DUST

    Much depends on the extent of contamination; light dust is probably best left alone. If the dust is to a degree that the lens is losing its contrast capabilities then it should be cleaned. Make sure you know the source and treat this first by repair or removing the lens from exposure to it. All inner surfaces of the lens will be contaminated. Undertake work in a separate room. Use brushes and air blowers to remove dust, lightly polish element faces and clean and dry all components prior to reassembly.


    If you suspect the observed white spots to be balsam failure seek the opinion/confirmation of an expert. This repair can only be undertaken by experts if at all. It is highly involved and by inference very expensive. Unless the lens concerned is particularly rare the best strategy is to seek another example. Many Pen F lenses suffer balsam failure. Examine carefully before you buy and if at all suspicious don’t. Worst affected seems to be the Pen FT 42mm x 1.2 standard lens.


    Fungus is not just a nuisance, it can wreak irreparable damage to our equipment and can attack lenses, prisms, screens and mirrors as well as other parts like shutter blinds, tapes etc. While it can be removed from certain parts of the camera leaving little damage, it is when it attacks any of the optical systems it is at its most dangerous. Fungus is a major threat to lenses. Fungus can etch its presence into the surface of the glass and cause permanent damage to the lens performance. At worst it can alter the surface and curvature of the lens rendering it useless. A ‘milder’ attack on the coating(s) will reduce the lens’ performance, especially its contrast. If left too long before removing the fungus will not resolve the problem as the lens elements may have to be replaced. This is an expensive process even when parts are available. With older lenses the problem is more acute and might lead to the heartbreaking decision to bin a lens. It is a problem best avoided at all cost; prevention is infinitely preferable to cure.

    Fungus is a life form. Like all other life it requires certain essentials for growth; time, temperature, food, moisture and harbourage. Fungus appears in two basic forms; its active state which can be observed as a colony of growth with small white or coloured blobs (fruiting bodies) and associated tendrils of mycelia appearing web-like, spreading over the surface it inhabits. Its second form is invisible consisting of fungal spores which inhabit the air all around us in large quantities. As individuals we can only deal with the active fungus as and when it occurs, spores can only be effectively removed by highly sophisticated air treatment filtration and conditioning plants. Given the right conditions fungal growth is universal. Fungal spores are an essential part of fungus reproduction.

    So how does it work then? The successful fungus needs to reproduce and it does this not only by continually dividing and growing where it is but by colonising other areas and to this it needs to travel distances. The most effective way is to produce a tiny air-borne spore which has within it all the genetic information needed to reproduce the mother ‘plant’ if the spore falls somewhere where life conditions are met. The mature fungus’s fruiting body produces millions of these invisible spores into the air, thus ensuring colonisation and continuance.

    Knowing the basic life necessities for fungal growth is essential to our understanding and how we can stop or discourage its damaging growth. There is little we can do to reduce the time factor for our equipment might sit on our shelves for years. The same goes for harbourage for the fungus is likely to ‘infect’ our equipment if other conditions are met. Food takes a little understanding, but the mycelia can absorb minute amounts of sustenance from apparently innocuous things like lens coatings and balsam glue as well our fingerprints and dust that settles on/in our equipment. So there is something we can do to remove (partial) food from the life equation by ensuring we keep our equipment dust and greasy fingerprint free. That leaves temperature and moisture and controlling these two aspects can reduce and/or remove the threat of fungal growth.

    Anyone who has dealt with house condensation is well on the way to understanding how to prevent fungal growth. The basic principles are the same. The warmer the air the more moisture – water vapour - it can hold (humidity). Thus in hot and wet climates the humidity is high but in hot arid regions the humidity is low. Moisture arises from many sources and in the home we are one of the main offenders, alongside kitchen, laundry and bathroom activities. Stagnant, slow and non-moving air harbours moisture. The basic cure is to increase levels of dry heat as well as increasing ventilation. The drier the air the less moisture it can hold. The more ventilation there is the more the air moves and the less moisture is likely to condense.

    • Problem: Air holds moisture and spores. Moisture condenses out onto colder surfaces. Spores need surfaces and moisture.

    • Solution: Decrease humidity, increase ventilation and air movement, add dry heat.

    How do we apply this to our photographic equipment? First look at where it is kept. If your collection resides in a room or part of a room and is on open display then you must deal with the room as a whole. Is it warm and dry? Is it well ventilated? Are there other items in the room that help with heat and ventilation? Are there activities in or near to it that cause moisture? If it is in cabinets are these preventing the circulation of air? If it is on shelves is there enough ventilation to move the air at the back of the shelf?

    Treatment depends on degree and varies from cleaning to binning. Remember to isolate the offending lens and undertake any work in a separate room. The experienced DIY repairer can deal with light fungal attack but for heavy and/or persistent growth, seek professional advice. Once stripped down tendrils and webs can be removed with household vinegar or a cleaning solution of 50:50 hydrogen peroxide and household ammonia. Olympus technicians are taught the following:

    Use Ponds Cold Cream or similar. Rub a tiny dab into the lens with your finger tip and then clean off with denatured alcohol. If fungus’ “spider web” remains, re-apply cream, rub harder and then clean with alcohol again. Do this at your own risk; not for the faint-hearted. [Source: A major Olympus repairman in US via Internet.]

    For heavier invasions where the fungus has etched its presence into the coating and/or the glass surface there is little that can be done. If you can feel the etching with your fingernail it is already too late. Re-polishing might be possible but this means the coating will be polished off at best or the curvature of the element altered at worst. Re-coating can be done but it is hugely expensive. In worst case scenarios binning of the lens is the only solution as displaying it with your collection might prove an unwise move as even when cleaned it is still a likely source for spores.


    These can be bought commercially or made at home. Basically it is a box with a light/heat source in the bottom with shelves above. It is closed but ventilated. The bulb creates heat, heat rises creating ventilation, air is dried and your equipment on the shelves is protected. Degrees of sophistication are in-built like timers and temperature/humidity sensors; it depends on how much/little you wish to spend. Home made versions can be achieved using small low wattage fluorescent tubes in the base of plastic or even heavy cardboard boxes with open shelves above to let air circulate. Although heat generation is limited please be aware of fire hazard!


    A lower tech solution that is available in many guises from clothes storage to food preservation and in a host of sizes. Known as Baggies these are heavy duty clear pliable plastic bags with a seal. As long as air can be removed from the bag and it can be sealed this offers an alternative. Wrap your dry equipment in bubble-wrap and place in the bag. Remove the air and seal. It is advisable to include bags of silica gel amongst your gear to absorb minute amounts of moisture when using this method. Not the most convenient solution but much depends on how much gear you have to protect and how often you need it.


    Without doubt avoidance is the key. Take great care when adding to your collection that you don’t import a source of dust or fungus. Early diagnosis is essential so keep checking your gear. Keep it clean and dry and use it often and sensibly. Seek professional opinion. Don’t tackle repairs without knowledge, experience and tools.

    With thanks to J Foster, Editor and the Executive Committee of The Olympus Circle, in whom all copyright vests.



    Posted 26/Feb/2005 14:04 Copyright © 2004 John Foster