Fungus - latest thoughts?

Folks, is fungus on internal elements really a no-hoper?

I've recently acquired a stonking 75-250mm zoom that is generally in very good condition but at least one internal element is contaminated, it's quite bad but doesn't really affect the image quality.
Being an old lens, it's not worth much and certainly not economical to clean/repair professionally - should I just bin it?
Fungus spores can't be killed by UV-C light because of the multi-coating on the outer elements but keeping the lens dry and well ventilated should prevent further damage but is there really a risk of contamination to my other lenses and equipment?

I guess I should err on the side of caution and throw it away but it seems such a shame

The fungus spores were presumably already in the air, which is how they got into your lens, and I'm not sure I'd want a source of contamination near my other photographic gear, especially not in the confined environment of a camera bag....Personally I would dispose of the lens just in case. If there is a risk and it spreads to your other gear it could be a very expensive way to find out.

Some threads on the subject:
http://www.photoethnography.com/blog/archives/2005/03/keeping_cameras.html
http://homepage.mac.com/mattdenton/photo/cameras/repairtips.html
http://www.europa.com/~telscope/fungus.txt

Maybe there's something in that lot
Matt

Thanks chaps, excellent links Matt

I guess I've got nothing to lose by attempting to take it apart and give it a clean........it'll be an interesting project anyway.

In the meantime, I'll keep it well away from the other stuff and it's only been on a camera for a minute or two - just to see how good (or bad) it was!

I think I'll have a go at cleaning it up and leave it for a while to see if it gets any worse, the image quality appears pretty good as it is, so I think it's worth trying to give it a new lease of life

Hi Kimbo,
Just a few thoughts on fungus based on personal experience/research and discussing the matter with both Mike Spencer and Robin from Harrow Technical. In all I have had about 8 lenses suffering from Fungus. 6 cleaned fairly easily, one was difficult and the last was damaged well beyond repair.

The whole question of fungus is complicated and difficult. As plants they are a very succesful group and there is no way we can avoid the spores. The problem is how do we stop them affecting us. As a group they like damp conditions and have no chlorophyll, so do not need light and can prefer to be without it. They are also very good on feeding on old organic and other matter. (Hence the phrase "like mushrooms, kept in the dark and fed on ... ). Light especialy UV will kill a fungus but not get rid of it and I doubt it will affect the spores which are very hardy and so small that they can be carried on air. We, therefore, have to assume that we will be subjected to them regardless of whether there is another fungus lens around or not. You can stop them germinating by keeping your equipment dry and preferably not in the dark all the time. Perhaps this is a good argument for using a filter to protect the lens rather than a lens cap.There are also several varieties and I have seen noticeable differences in the way they look, how easy they are to get rid off and how much damage they do. One sort has the very fine tendrils. It was this sort which totally wrecked the lens and I suspect produces more hydro-flouric acid than the others. Another appeared like a very small clump and was easy to remove. The last was in between. I am not a botanist so I can't give you the names.

Once the fungus has been killed, it is probably not much of a problem in the same way that once woodworm has been treated it is safe to keep it with other furniture. The spores may give a slightly increased risk but I suspect not as much as damp dark conditions. With primes it is relatively easy to get at the elements to clean them. With zooms it can depend on the construction. I had one where I could get at the elements without dismantling the zoom/focus mech so was not too much of a problem. The important thing is to remember or better still take notes of how the elements came out or as one of the links said, you could end up with funny results!

As to cleaning the elements, the easy ones came off with a microfiber cloth perhaps with a small amount of lens cleaning fluid or lighter fuel. On the more difficult one I used Flitz which is sold by Micro-tools as a polish. It probably is a very mild abrasive but I couldn't see any damage with the naked eye. Further than that I couldn't say. Some swear by Pond's cold cream. With the last lens, the Flitz did take the fungus off but the etching of the glass was apparent.

IMHO, you have nothing to lose by trying. In it's present state, you will probably have to bin the lens so if you make a mess of it you can still bin it but will have learnt something in the meantime which might help save a more valuable lens later. And if it works you will have gained the experience as well as the lens

Kim

Thanks Kim, the fungus only really affects one internal element and is clearly visible when looking through from front to back.
When I get a chance, I'll have a go at posting an image for you - that'll be an interesting project in itself!
The lens is a one touch zoom with 13-elements in 10-groups and the offending glass looks to be in one of the middle groups - nothing like jumping in at the deep end eh?

If it gets worse, it'll soon affect the image quality but it's not really noticeable through the viewfinder at the moment.

You think the risk of cross-contamination is minimal, that's a relief but I'll certainly be taking the suggested precautions.

Just to emphasis something I said, it is worth trying to make sure the fungus dead before keeping it with other lenses. Once dead it cannot produce spores but it will do so if still active and this would produce some risk.

Kim

Here's a pic. of the lens in question:


http://hongkongfuey.blogspot.com/

I wouldn't call that quite bad, compared to some I've seen, and I am sure it would have little effect on image quality. Any etching of the glass that might have occurred would be very minor.

However, it could get worse, and the lens now is of little value. I'd pull it apart ASAP. You may never be able to put it back together, but at least you'll have some fun trying.

G

PS: Do you live in Hong Kong?

Hi Kimbo,
That looks to be the intermediate form of fungus I was talking about. It may prove difficult to clean but I doubt it will leave much etching. Depending exactly where it is, you may get away with just removing the front group and reaching it with a cotton bud or similiar. If it is on the back of the middle group try taking out the rear group. If it's in the middle, lots of work!

Regards
Kim

I'm quite relieved that you don't think it is too bad, I've only seen a couple myself and this is the worst one. The element in question appears to be toward the center but with any luck it'll be at the back of the front group or the front of the rear one but either way I suspect a considerable amount of disassembly will be required.
I've just got to find the time to get started but for now, I'm leaving the lens with caps off, in the window sill to help inhibit further growth.

err...no I don't live in Hong Kong but I needed a name for the blog and others I tried weren't available, I rattled off some random letters on the keyboard and it looked like hongkong - so I thought what the heck!
It was my first attempt at a blog and I'll improve the appearance, once I've figured out how to edit the layout (I'm not really happy with it as it is but I think it shows the fungus quite well).

Thanks for looking George and Kim, and for your encouraging comments.

Of course, the best thing would be to send it to Kim, as he's a bit of an expert. Just tell him you think digital is dead, and he'll have it fixed in no time.

G

(Just joking, Kim!)

Please don't suggest that. I have just finished 6 FSU lenses for a guy in Canada that needed a complete strip and relube! I need to catch up on some of my projects and then I may even get out to take some photos.

Kim

I'll have to give that 'flitz' stuff a try.

I've been looking at the description on micro-tools, and it sez it's non-abrasive, but I wouldn't bet the family silver on it!

As for whether it will infect your other lenses or not, I seriously doubt that the risk of infection is increased in any significant way. The air is full of fungal spores of all sorts anyway, including the kind that eat lens coatings. The funguses which eat lenses are the same sort that live on rocks and stuff in the 'natural' world and are encountered just about everywhere. So it is almost inevitable that all your lenses have fungus spores in them anyway.

The real trick is not to provide the right conditions for growth, so clean dry conditions are indicated. Once established though, the fungus will just become dormant if the conditions are not right. As for killing the existing infection, UV will probably do the job, but as already pointed out, the spores are much more robust. (Enough UV will probably penetrate far enough despite coatings anyway, especially if you give them a couple of days on the sunbed!)

In most cases you only see fungus on lenses that have been very poorly kept. I know of at least one case where the lenses were kept permanently in the kit-bag, which would inevitably get rained on from time to time. It certainly didn't help that they were expected to keep company with the owners sandwiches. Neither it seems was the kit bag ever cleaned. The amount of organic gunk floating about in that bag must have been horrendous.

It never ceases to amaze me how careless some people can be over stuff which may have cost them hundreds of pounds. (Iv'e also noticed that those who are the worst offenders are also the loudest complainers.)

As for taking the lens apart. If you are careful, take notes, and mark the relationship between parts before you remove them, it should not be too difficult.

Just take care that you use the proper tools (Micro-tools again!), and don't try to force anything that dosen't seem to want to come off. Take special care not to get finger marks etc, on the lens surfaces, and note down which way around and inwhat order any bits of glass you remove came out. (You don't want to be cleaning any glass that wasn't dirty before you got your greasy mitts on it. That's just going to increase the risk of adding a few scratches. Or 'cleaning marks' as some describe them.)

Hi,
I find micro tools to be very, very expensive. In most cases an equivalent quality tool can be bought at any good hardware/model shop at about a 1/3 of the price and most "special" tools can easily be fabricated. I have made a set of 3 special spanners to remove thelens elements from Canonets, 2 were made from old paint scrapers and the third from a piece of brass stock and some high grade piano wire. Total cost aout £3, to get tools from microtools to do the same job would have been abut £55!

Kim