[bygp]

I've got a Vivitar series 1 (Kiron) 70-210mm with a perfect smooth zoom pump & focus ring, clear front lens, clear rear block but lots of fungus on the middle optical bloc, just between front lenses and diaphragm. This makes this lens almost unusable for sun-facing shots, even with a hood. It's easy to remove the front lens, but I've not yet been able to unscrew the middle block rings, even using acetone to remove lock-it glue or taping on it, it's realy sticked, so I can't access the lens where fungus are. Dismounting by the rear seems quite hard too, the rear block is easy to remove but cannot go further atm. Is there any way to suppress fungus with UV or any other E/M waves ? I had it for a low price but wasted if I can't remove these fungus. Thanks for any dismounting advice or any tips on other ways to suppress these fungus.

[Elroy Jetson]

The rings may respond to heat from a heat gun or hair dryer. I've had better luck with heat than anything else. Good luck.

[jatrax]

Is there any way to suppress fungus with UV or any other E/M waves ?

Your fungus is dead already, what you see remaining is just the filaments. No way to remove those without access and cleaning.

UV or heat can kill fungus, if it was still alive, but lens fungus is almost always dead, it generally lives a very short time, hours or days until it runs out of nutrients or moisture. If it was not dead, and still growing, it would soon fill the entire lens and be growing out all of the access ports. But of course that never happens because there is no food in the lens to sustain that amount of growth.

[Digitalis]

Is there any way to suppress fungus with UV

A 1Kw 355nm optically pumped nitrogen UV laser should do the trick. It also might decompose the optical cement and cause it to ignite, which should make for a fun evening.

The rings may respond to heat from a heat gun or hair dryer.

There is also a chance of the adhesive between the lenses will also respond by separating.

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Last edited by Digitalis; 11-25-2015 at 12:24 AM.

[UncleVanya]

Send a pm to DCShooter he may have some ideas.

[bygp]

Here are the repair manual and notes: Page 40

MEK tends to work better than Acetone on Kiron/Vivitar threadlocker.

Clean the affected elements with plain warm soapy water, rinse in distilled water, and clean any remaining residue with a Kimwipe or clean microfiber.

Yes but I can't find MEK where I live. I just sent a message to the seller to tell him I was upset because nothing was mentionned in his item description, asked for a refund, I had it for a low price, I now know why, but 25 euro is still money and if he don't refund me I'll find a way to ruin his e-bay rating ! Hate these types of e-bayers, just stealers. He knew very well this internal lens was full of fungus and did not mention it. I won't go further in trying to fix this lens, time is money too.

[RKKS08]

@jatrax
A couple of months ago I would have written the same as you just did, and I passed the same suggestions to others. But meanwhile I found some information which makes me wonder whether I was wrong:
I was baffled to read that far-UV (high frequency) kills fungi and its spores, but blue light and near-UV can reactivate spores which seem to be dead. And once a zoom lens gets use again, the zooming effect will transport a lot of organic material together with the air inside the lens.
The effectivity of UV light seems to depend strongly on frequency.

You can have a look at Microbiological Research, Vol.151,Iss.1 from 1996.
There is an excerpt on the net
https://www.sciencedirect.com/science/article/pii/S0944501396800504

But, of course, this is not about the kind of fungi you will find in coated lens arrangements. I don't know whether scientific research about these exists. The industry may have looked into the problem, but if they found means to long-term prevent fungi in lenses, they may have classified it.

I think the best tool would be a sunray lamp of the sixties, but these are probably not available anymore. The high frequencies ("far-UV") which are most effective against fungi are the same which cause skin cancer. And there still is no guarantee the DNS of all fungi spores is broken in a way it can never re-arrange. Fungi which seem to be dead just by starving should have produced enough spores to start a new life once they get food (and moisture) again. Fungi spores can survive for centuries, and then start building a new colony.

[UncleVanya]

Yes but I can't find MEK where I live. I just sent a message to the seller to tell him I was upset because nothing was mentionned in his item description, asked for a refund, I had it for a low price, I now know why, but 25 euro is still money and if he don't refund me I'll find a way to ruin his e-bay rating ! Hate these types of e-bayers, just stealers. He knew very well this internal lens was full of fungus and did not mention it. I won't go further in trying to fix this lens, time is money too.

Don't put up with it. Open an Ebay dispute. I did that vs. a seller that claimed to be selling an 8 element takumar - it arrived - it wasn't. I had to argue over and over and finally I gave up and opened a dispute. It took about a week - I provided evidence of the lack of correct description and they sided with me. I sent the lens back postage paid (by ebay policy the seller is charged for that) and I was refunded my money in full.

[RKKS08]

The OP seems to be from France, and eBay may handle this different depending on countries.
In Germany, no problem if payed with PayPal, or the offer was marked with "eBay guarantee" (which seems to depend on the status the seller has with eBay).

3 years ago, they also gave me a refund when these conditions were not met, but expressed this was "good will" and an exeption.

Lately an item never arrived, and the seller did just not answer (but had new offers); eBay did nothing even after a dispute, and did not even comment on it.
I later found out the seller ran out of money with his business; so my guess is that they show this kind of good will only if they are sure they can get the money back from the seller.

But of course it's always worth a try.

[jatrax]

A couple of months ago I would have written the same as you just did, and I passed the same suggestions to others. But meanwhile I found some information which makes me wonder whether I was wrong: I was baffled to read that far-UV (high frequency) kills fungi and its spores, but blue light and near-UV can reactivate spores which seem to be dead. And once a zoom lens gets use again, the zooming effect will transport a lot of organic material together with the air inside the lens. The effectiveness of UV light seems to depend strongly on frequency.

Don't misunderstand, I meant only that UV CAN sometimes kill fungus. And I have read enough studies to know that "sometimes" is the operative word. I most definitely do not advocate its use. Doing so with lenses is a waste of time. Those reporting success miss that the secondary effect of using UV light is to warm up and dry out the lens, thus stopping any fungal growth. If indeed there was still any. The same thing can be achieved using desiccants or a dry box.

I have seen numerous lenses with fungus, I have NEVER seen one with actively growing fungus. Dormant and viable spores, yes. Growing filaments, no. And as you point out fungal spores are present in the air so even if you open and sterilize a lens as soon as it is exposed to the air it will again have spores present.

The ONLY effective means of fungal control in lenses is to keep them dry and if they get wet to dry them as fast as possible. People in very humid climates are well advised to use a dry box for lens storage.

---------- Post added 11-24-15 at 08:06 PM ----------

There is a difference between 'killing' fungus and removing the noticeable filaments. It is almost never necessary to 'kill' fungus as it is already dead. And removing or trying to kill the spores is futile. Removing the filaments requires physical access to the part of the lens the filaments are on.

In most cases when people talk about removing or getting rid of fungus they think in terms of 'killing' it but instead they should be thinking of just cleaning up the mess the fungus left before it died.

[bygp]

Here are the repair manual and notes: Page 40

MEK tends to work better than Acetone on Kiron/Vivitar threadlocker.

Clean the affected elements with plain warm soapy water, rinse in distilled water, and clean any remaining residue with a Kimwipe or clean microfiber.

Thank you very much for this precious "page 40" link, reading these PDF helped me a lot, I've been able to totally dismount the zoom and access the faulty lens which is now crystal clear (chloridric acid, then 90° methanol, then wet cleaning). It's gonna take a while to mount it back, but will also allow to re-lubricate all parts to have a 'like-new' pump. Hope I'm not going to fail in mounting it back, not that easy...

---------- Post added 11-24-15 at 09:17 PM ----------

Don't put up with it. Open an Ebay dispute. I did that vs. a seller that claimed to be selling an 8 element takumar - it arrived - it wasn't. I had to argue over and over and finally I gave up and opened a dispute. It took about a week - I provided evidence of the lack of correct description and they sided with me. I sent the lens back postage paid (by ebay policy the seller is charged for that) and I was refunded my money in full.

That's what I've done, meanwhile with the PDF tech. doc one of you posted the link, I've been able to access the faulty lens which is now crystal clear...

The time I spend fixing that is more than 25 euro so I'm going on a refund while keeping the fixed lens, if I'm able to mount it back properly

[RKKS08]

@jatrax
Fully agreed.
A while ago I did use a strong old sunray lamp for a SMC-M 4/50 macro which showed small traces of fungi just near the borders of one lens element.
Because of position and small amount it was difficult to see (so I found out only weeks after eBay purchase and couldn't return it anymore).

It doesn't influence IQ and I used UV only to make sure it won't grow again (20 minutes in a distance of 40cm, so it would not get too hot).
At least I think it did no harm.

[Digitalis]

I don't know whether scientific research about these exists. The industry may have looked into the problem, but if they found means to long-term prevent fungi in lenses

There actually has been considerable research,as fungal activity can affect a number of industries - silicon fabrication, aerospace engineering, nanotechnology, pharmaceutical fabrication etc. I have several papers regarding fungal growth on silicon substrates dating from 1986 to as recent as 2004 - the general consensus is that softer glass (such as common varieties of ED glass) with high amounts of elemental Phosphorus,Magnesium, Zinc were more favorable to fungal growth, and harder glass types with higher concentrations of heavier elements such as Lead,Thorium,Lanthanum were generally more resistant - especially to the fungal enzymes that lead to etching of the glass.

[manntax]

The time I spend fixing that is more than 25 euro so I'm going on a refund while keeping the fixed lens, if I'm able to mount it back properly

I don't think you are entitled to any compensation / refund once you have disassembled the lens. As far as I know eBay will not side with the buyer who was tinkering with item and disassembled it. You were entitled for a full cover when lens was in exactly the same condition as you've received it. Now I don;t think it is even possible for you to claim anything . You should have waited for the result of the dispute and approach the lens only when you (or the seller ) commits/confirms that the lens is yours and there are no further doubts about the ownership of the item.

[bygp]

I don't think you are entitled to any compensation / refund once you have disassembled the lens. As far as I know eBay will not side with the buyer who was tinkering with item and disassembled it. You were entitled for a full cover when lens was in exactly the same condition as you've received it. Now I don;t think it is even possible for you to claim anything . You should have waited for the result of the dispute and approach the lens only when you (or the seller ) commits/confirms that the lens is yours and there are no further doubts about the ownership of the item.

The seller has been ok for a refund, I sent him a photo of dismounted lens, and he lets me the lens and I get my money back All lenses are now crystal clear, but mounting it is going to take a few more hours as I take this opportunity to lubricate the pump/focus mechanism with silicon grease and clean all parts, If I succeed I'll have a good lens with only some internal scratchs on lens locking rings... But this lens should have been sold for parts, not just as 'used'. Just shipping fees not refund. As we say here "don't sell the bear's skin before you killed it" and le lens is still disassembled atm^^