Mushrooms expert opinion needed

[truls]

I may have a lens With mushrooms, Minolta Rokkor X 50 1.4. At the right inside of the lens there is "something". I have never seen this before, is it clean-able?

[Stephen]

It may be cleanable, if not left for too long, use distilled water, a spot of detergent, and a dash of hydrogen peroxide solution. Wash the glass and dry with microfibre cloth straight away. If the fungus is left too long it may eat into the coating and glass, etching a mark, even if removed. Hydrogen Peroxide is optional, it may affect some coatings if used too strong.
The marks do not affect the image that much, mainly lower contrast. Try to keep lenses in warm, dry conditions to fend off any fungus attack.

Stephen.

[lloydy]

I've cleaned worse fungus than that with cold cream, the stuff women use to remove make up and keep their hands soft. It works really well, just plaster it on the lens, leave it for a while and wash off with Zippo lighter fuel or warm water and dish soap.
I've tried the hydrogen peroxide as well, and that works perfectly well. But my my wife doesn't use it, but she does use cold cream.
That amount of fungus probably hasn't etched the glass and won't affect the picture quality noticably. I've got two of those Rokkor 50 1.4's and I love them, so sharp and lovely colours, it's a great lens.

[genazzano]

I guess I've been lucky not having run into serious mold problems until now. Just got a Perfex 33 and the lens is moldy.... really moldy. I will be discarding it and search for a cleaner one.

My question is does anyone have experience in having the mold return after a cleaning? Unless extraordinaryly thorough sterilization is done, and it rarely is, the mold spores remain in the lens housing and mounts. So, I would expect that the mold would return at some time.

David

[lloydy]

My view is that the mold spores are in the air, and it's more about the storage of lenses rather than the risk of infection from another infected lens - or the fungus returning to a cleaned lens.
I have many lenses that have had fungus which I've cleaned and it hasn't returned. Some were cleaned over 5 or 6 years ago and not one has become reinfected.
Many years ago when I didn't have time to use my equipment for a few years I stored it all in a metal cabinet that was under the stairs of the house where I thought they would be safe. Every lens was badly fungused on just about every element when I took them out, most were totally ruined by the fungus etching the glass. The problem was, the cabinet was the ideal place for the spores to flourish and become the dreaded fungus, it was cool, slightly damp ( it's a very old house with no modern damp proofing or ventilation ) and it was dark, the metal cabinet made it worse because it produced condensation. Absolutely perfect for the fungus.

Now I store my lenses in my den, where I have dehumidifiers keeping the moisture below 40%, it's heated during the winter, well ventilated, the lenses are in opaque plastic storage boxes with the lens caps off to allow UV light to get in the lenses. I haven't had one lens, in well over 100 lenses now, infected or reinfected since I adopted this regime. I will even buy a lightly infected lens at a cheaper price with a view to cleaning it with no worries now.
And I don't store infected lenses in a different place either, because I believe that I have created an environment where the spores can't flourish into fungus. The best prevention is using the lens, get the UV light on the glass, then keep them as dry as possible.

The storage boxes I use are not airtight either, I like the dehumidified room air to circulate as this greatly reduces the possibility of condensation forming inside the containers. There is a school of thought that air tight containers should be used, especially in high humidity / tropical climates. Which is probably OK as long as a lot of dessicant is in the boxes to mop up any moisture caused by condensation


Box two Long lenses. Explore 352. by Mudplugga, on Flickr


Box one small lenses. by Mudplugga, on Flickr

These are superb storage boxes, really strong and adaptable, from the 'Really Useful Box Company'

www.reallyusefulproducts.co.uk/uk/html/onlineshop/fullrange_rub.php

I use the 21 Liter boxes with the removable divided trays.

[genazzano]

That's encouraging. I'm a mammalian cell biologist and don't know jack about mold except that it's a pain. We used fungizone, i.e. Amphotericin-B, to keep common mold from growing out in cell culture medium before the advent of effective clean hoods. We all have read endless opinions on fungal growth on lenses but not much regarding what kind of mold is responsible. To etch glass it would have to produce some impressive stuff, presumably strong acids. You're right about the source which is probably common airborne spores and sterilization of lenses would be an exercise in futility. Thanks for the telling about your experiences after the lenses have been cleaned.

David

[lloydy]

I have no biological background at all, I'm an engineer, but I have a friend who is a mycologist and is studying ways to isolate bacteria and fungi that 'eat' materials that are considered waste and non biodegrable such as plastics. After baffling me with science he gave me the simple explanation that some fungi are closely related to lichen, and they excrete enzymes that dissolve the material they settle on to get at the nutrients they need. I think that's the simple explanation anyway, we were having this discussion over a few beers !

[genazzano]

Can't think of a better place to discuss mold than over a pint or two.

[matty]

Hello Stephen,
I saw your advice about cleaning fungus from lens, I had a box of bits and bobs from a car boot and at the bottom was a few enlarger lenses, one Meopta and a couple of others. They all have fungus and I thought they would be only suitable for the bin. If I cleaned them as you described would they still be useable if marked (I only did printing the once about 25 years ago using the university archaeology department darkroom, so know very little about the mechanics of using an enlarger.)
Thanks
Matty

[Stephen]

As long as the basic fungus is removed on the enlarger lenses, then all should be all right, as enlarger lenses can be in quite bad condition and still work fine. Most darkroom work is in black and white, and the only effect would be very slight ghosting, and lowering of contrast, both of which can be minimised by using a higher contrast paper, a harder grade, and fuller development of the papers.

For printing portraits such lenses may be better than a cleaner lens.

Basic Colour printing would be OK, but it might cause colour shifts due to the stray ghost light, and need careful set ups to get consistent colours across a range of negative subjects.

Stephen.

[lloydy]

Fungus. by Mudplugga, on Flickr

Nasty lens fungus etching.
This is a big macro of the damage done to a lens element by the acid etching of fungus. The element has been cleaned using the tried and effective method of plastering it with cold cream then washing with Zippo lighter fuel, which cleaned the fungus off very effectively.
But if the fungus has been there a long time this kind damage will remain, the fungus secretes an acid that eats into the glass and damages it beyond repair.
This element is so bad it barely passes light, the lens is scrap. The main body of the fungus was on the most damaged part of the element, but the remaining surface, both sides, had the lighter damage which resembles the frosted glass for bathroom windows. The etching of the element was deep enough to feel with my fingertips. Also, this was the only element in the lens that had any fungus at all, the other elements were perfect. But I'm not too broken hearted, it was a junk Sigma zoom that was a freebie.

The macro was done using the Sony NEX5, a Pentax PK fit Miranda 75-200 Macro zoom that does a genuine 1:1 macro, and then I put a Zeiss Tessar 50mm reversed on the front of the Miranda, I have no idea what the final macro magnification is but it was big.

[genazzano]

I'm going to try this lens that came along with a Perfex 33 that I just got. The mold is so bad it looks like a piece of cheese. Not optimistic...I wonder if anyone has definitively id'd the fungus that eats glass.

Lloydy: The link has broke in your previous posting. BTW, I like your photo work.

[Stephen]

Not sure which fungus is involved but the acid left is hydrofluoric, according to lens experts. If the glass is cleaned properly, and the mount washed, no fungus remains. A fungicide can be used or caustic solutions, or other strong acids to wash and clean the items.

The damage to the surface remains, the etching can eat several microns into the glass.

In the case of un-coated glass, the surface can be re-polished by optical manufacturers, and it could be tackled by a home machinist if you build a grinder head. Hand polishing can also work, as the curve is established, and a surface grind applied by a "hard leather", and several grades of cerium oxide will remove the marks. However this is not for the faint hearted, it takes hours of grinding to do each stage, and a mechanical grinder is better.

However the damage may not be as serious as it looks, haze can be removed with suitable fine grade compound or cleaners, and a clean lens with etch marks will work, not well, but work.

Coated lenses will need re-coating after the finishing and this is not an easy or cheap process to find these days for repaired lenses.

A dry lens will never suffer from moulds, it needs damp and warmth to get started, so after removal it should be all right if kept really dry.

For the Perfex lens, this may be very bad, and if is is bad, then risking polishing with compound could be done. It must be viewed under strong magnification to determine the surface damage, dirt on the outside or etching inwards. You can clean the outside with compound to remove the dirt, brasso metal cleaner can be used, or buy in cerium oxide in fine grade,(Optical grade Rouge). This will not repair the etching damage.

Stephen.

[lloydy]

I've relinked the pictures, I think flickr has changed the URL information as part of "making flickr awesome" - I'll check my other posted pictures and try and embed them so they are permanent.