Fungus

[Chris W]

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I have an old 1980's M Summilux 50mm F1.4. Some months ago I tried to trade it in on some new camera equipment. It was rejected by the store on the basis of 'some fungus visible with loupe'. I'm not questioning that.

The lens still takes very nice images (I'm not sure how bad the fungus is, probably not bad).

I was thinking of selling it for parts, but again, it's still very usable.

Advice: Should I just keep using it. Should I try and have it repaired (fungus cleaned), if so is there anyone reputable (preferably in the UK).

Here's test shots from today, first at f1.4, then f5.6.

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[84bravo]

Just use it as is.

[Chris W]

I guess it will deteriorate over time?

[wda]

Your lens is usable. It is too good to be sold for parts, assuming there is a market for such. Clearly the lens will be worth less than one in better condition. 

Some dealers carry out servicing,  at a cost to you, reflected in their valuation.  I would get a few quotes first. Then decide if it is worth you keeping it. I think it would be excellent for flattering portraiture. 

[graphlex]

Skyllaney gets good reviews here, and they offer fungus removal on their site.

Edited April 7, 2024 by graphlex

[Ivar B]

2 hours ago, Chris W said:

I have an old 1980's M Summilux 50mm F1.4. Some months ago I tried to trade it in on some new camera equipment. It was rejected by the store on the basis of 'some fungus visible with loupe'. I'm not questioning that.

The lens still takes very nice images (I'm not sure how bad the fungus is, probably not bad).

I was thinking of selling it for parts, but again, it's still very usable.

Advice: Should I just keep using it. Should I try and have it repaired (fungus cleaned), if so is there anyone reputable (preferably in the UK).

Here's test shots from today, first at f1.4, then f5.6.

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Simply register for free here – We are always happy to welcome new members!

You should most definately NOT continue using it. I do recall that Leica at one point of time refused to accept fungal lenses as they were frightened that the fungus might spread. If a lens was fungal, it had to be sent to a special repair shop in Hamburg as I recall, which would kill fungus. I recall this happened to a friend of mine with an 1.0/50mm where Leica refused to accept the lens and also said that the required procedure would bee too expensive. He was able to find somone else, though.

It this is too strict I cannot tell nor am I certain that Leica still has this policy but I would take great care so fungus does not spread to my other lenses. 

[earleygallery]

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Many seem to think fungus is a complete write off. You can have the lens cleaned, depending on the amount of fungus and how long it's been there, it may not be able to remove all traces (it can etch the glass) but it should kill/stop it.

You can also leave the lens facing sunlight, aperture wide open and the UV will kill the fungus and stop it getting any worse.

I suspect from the images that it's not too bad and the lens is useable and still of value - just less than a perfect copy of course.

[pgk]

2 hours ago, Chris W said:

I have an old 1980's M Summilux 50mm F1.4. Some months ago I tried to trade it in on some new camera equipment. It was rejected by the store on the basis of 'some fungus visible with loupe'. I'm not questioning that.

Firstly check that it has got fungus.

If it has then most reputable repairers will be able to strip and clean it (and service it whilst they are at it) and it will most likely show no signs of any problem after cleaning.

I have the distinct impression that fungus is one of those things which has to be pretty bad before it damages a lens to the extent of being unusable. At worst it is usually cleanable, there is rarely in my experience any etching and even if there is (which would basically mean an 'infested' lens which fungus quite distinctly and the effect of it would be obvious in the resulting photos) then after cleaning it is unlikely to have a dramatic effect.

FWIW I have a number of old lenses described by auctioneers as having fungus. None actually do have any though. And I've had lenses cleaned of fungus in the past and the only one to have any significant damage as a result was a Tamron 500mm mirror lens. Mirror surfaces are delicate.

Get it cleaned and serviced and it will be good as ever and worth a lot more. And don't worry about it.

[GFW2-SCUSA]

34 minutes ago, earleygallery said:

Many seem to think fungus is a complete write off. You can have the lens cleaned, depending on the amount of fungus and how long it's been there, it may not be able to remove all traces (it can etch the glass) but it should kill/stop it.

You can also leave the lens facing sunlight, aperture wide open and the UV will kill the fungus and stop it getting any worse.

I suspect from the images that it's not too bad and the lens is useable and still of value - just less than a perfect copy of course.

I have had fungus on a lens (not a Leica lens) and did just what earleygallery said. I put it out in the sunlight so the sun filled the lens which was on a white board and left it for some hours. It helped a lot. Also putting it under a UV light will also work. Mine (which I inherited) was quite bad and seems to have etched the glass a bit.  If your fungus is a tiny spot the sunshine or UV light should clear it up. One thing to remember is not letting the lens get too hot which would dry up the lubricant, I assume.  As others have said, there is not reason not to use the lens and certainly it is not ready for the parts bin!  

[Chris W]

Know anyone in the UK?

Yeah, it's an old lens and I lived in a slightly humid part of Australia for ten years. But I can't see any fungus, if it's there it's a small amount and (understandably) the dealer wasn't inclined to buy the lens off me.

[Chris W]

Yeah, the images don't seem to be effected. Shot this a couple of hours ago. I'll try the sunlight approach.

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[earleygallery]

Shine a torch through the lens and look from the other side.

[pippy]

1 hour ago, Chris W said:

Know anyone in the UK?...

Not much use to you just now I know but, currently, I have a fungus-affected lens in with a repairer (whose name is brand-new to me) and it is booked-in to be seen 'on the bench' in six weeks(*). If you can hold out until such time as it comes back I can give you a report? His reputation, FWIW, seems to be very good.

As has already been mentioned it seems to be a good idea to keep it away from other lenses as there are numerous reports of fungus being able to spread from lens to lens if kept in close proximity.

Philip.

* Accodring to my booking reference e-mail? "Monday 20th May; 13:20" to be precise...

Edited April 7, 2024 by pippy

[spydrxx]

If you go the sunlight route, consider placing aluminum foil on the backside so you get the sunlight not only reflected thru once but also from the rear. Also wrap the exterior of the lens in aluminum foil to reflect the heat from the sunlight hitting it. I've used this technique quite successfully to clear lenses which have darkened due to radioactive  decay over many years. Just have to ensure proper positioning of the lens relative to the sun...adjusting it a couple of times/day. I'd expect fungus killing might take as long as a week or so of treatment. The laboratory I used to work in, used high intensity UV lights to kill fungus after their experiments with it, and usually exposed it to those lights a minimum of 24 hours.

[250swb]

Use it, it will take a LOT of fungus to impair the lens quality. But if you want to be sure it's dead and killed leave the lens fully open in UV light. A DIY cleaning solution is a 50/50 mix of hydrogen peroxide and ammonia but if it's internal that's when you need a techie type guy, but even then it will probably have etched the glass.

Edited April 7, 2024 by 250swb

[Chris W]

Thanks for all the advice.

[Chris W]

1 hour ago, pippy said:

 If you can hold out until such time as it comes back I can give you a report? His reputation, FWIW, seems to be very good.

 

Thanks, I can wait, no problem.

[Danner]

I thought (could be wrong) that the lens elements don't transmit UV light very well, so if the fungus is deep in the lens, the UV portion of the sunlight won't get in there as hoped.

[pgk]

12 hours ago, pippy said:

As has already been mentioned it seems to be a good idea to keep it away from other lenses as there are numerous reports of fungus being able to spread from lens to lens if kept in close proximity.

Fungus can only thrive under specific conditions - damp/humid, warm and dark - so its unlikely that it will spread unless these conditions are met. My lenses are kept in sealed boxes (Pelicases) with silica gel which I regularly replenish and recharge. So whilst two conditions might be met at times (warm and dark) humidity it kept low and the lenses don't suffer from fungus.

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Hallo,

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[Ecar]

13 hours ago, spydrxx said:

If you go the sunlight route, consider placing aluminum foil on the backside so you get the sunlight not only reflected thru once but also from the rear. Also wrap the exterior of the lens in aluminum foil to reflect the heat from the sunlight hitting it. I've used this technique quite successfully to clear lenses which have darkened due to radioactive  decay over many years. Just have to ensure proper positioning of the lens relative to the sun...adjusting it a couple of times/day. I'd expect fungus killing might take as long as a week or so of treatment. The laboratory I used to work in, used high intensity UV lights to kill fungus after their experiments with it, and usually exposed it to those lights a minimum of 24 hours.

Same thorium de-yellowing technique here. Except I use a 36W LED 365nm UV lamp in a cardboard box, which is faster than the sun (still needs at least a couple of days, though) and doesn't require repositioning. Also, it doesn't build up heat, so that the lens barrel can be wrapped in pretty much any light-blocking material to prevent it from bleaching. Worked quite well on a few lenses I tried this on. Given enough time, I can't see why it wouldn't kill fungus as well.

I am no expert and wasn't looking at killing fungus, but from the research I did back then, it seemed that a shorter, high-energy UV-C wavelength (usually 254nm produced by mercury devices) is actually even more effective against such nasties. IIRC however, the biggest issue is that (optical) glass blocks most of the radiation, so you might end up destroying any fungus on the surface of the lens within minutes, while the fungus that's inside would continue to thrive even after prolonged exposure. Also, UV-C is potentially a lot more dangerous for the eyes. Perhaps someone with more knowledge of physics than me could chime in?

In any event, fungus remains would need to be manually removed anyway, so I'd send the affected lens to a competent technician in the first place. Not a big or very expensive job, especially if done in the context of a full CLA. It seems like fungus on the OP's lens is barely noticeable and coatings on a lens from the 1980's are quite resistant, so I'd expect a successful outcome.

Edited April 8, 2024 by Ecar