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08-23-2018, 09:39 AM   #1
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New to Vintage Lenses—Fungus in 135mm Takumar Bayonet lens?

Hello. I'm new to the forum and to vintage lenses. I recently picked up a K1000 that came with a 135mm f/2.5 Takumar Bayonet lens. I noticed some spots which are visible looking through the rear element, but appear to be on the inside surface of the rear element. (See attached picture.) I think this is probably fungus. Agree?

I haven't developed the film I've shot with this lens yet so I don't know how much it will affect image quality, but with spots that prominent on/near the rear element, I can't imagine it won't seriously degrade image quality. Any suggestions as to the best way to deal with this? As this is a fairly simple four-element lens, I'm considering taking it apart to see if I can clean off the elements affected. What would be the best way to clean the rear elements without damaging the coating and the glass?


I'd rather not send it out anywhere, as the lens isn't worth that much and I don't want to spend any money fixing it if possible. I got such a good deal on the camera and outfit that I won't feel too bad if the lens isn't salvageable.


Thanks for any advice you can provide.

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08-23-2018, 10:53 AM   #2
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Kind of hard to tell without a macro of the spots. At first glance it looks like issues with the coating or separation of some sort. There are many more folks here who have a lot more experience ID'ing issues like this. You can find deals on similar lenses here in the for sale thread. (I have one there for sale now as a matter of fact!)
08-23-2018, 11:04 AM   #3
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Lenses with fungus are bad news. The spores can travel from the infected lens to an uninfected one quite easily. The more lenses you have, the more at risk you are if you bring an infected lens home.
Sometimes you can kill a fungus infection via dosing the lens with UV light for a period of time, but I just don’t think it’s worth the effort to risk a collection of lenses.
If you do have an infected lens and it is rare, expensive and desirable, send it out for remediation. If it is cheap, cheerful and common, trash it and move on.
If you live in a climate that is fungus friendly, do yourself a favour and check into dry boxes and the like for equipment storage.

Your lens may have fungus, but it could also be simple element separation or coatings damage. Fungus generally has tendrils or a spiderweb pattern. Either way, that lens doesn’t really look worth keeping.
Looking closer at the picture, I suspect fungus.
08-23-2018, 12:19 PM   #4
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I'd keep it separate from the others, just to be sure that - if its fungus - it won't spread. Then I would just take it apart to see whether it can be fixed and to learn from it. Even if you can't fix it, you'll learn and maybe even have soms fun.

08-23-2018, 12:22 PM   #5
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It looks like fungus to me also. As Wheatfield said, the lens isn’t worth much, but if you’re willing to put in the time yourself, you may be able to clean it. Buy a good set of JIS screwdrivers and take your time. I’ve cleaned a couple, some worked, some didn’t.

Good luck!
08-23-2018, 12:43 PM   #6
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The mount looks like they had dirt on it every time it was mounted! I suspect they did not keep it cool and dry when storing it either. Until I can buy a dry box, me lenses stay in a Rubbermaid style box with foam padding and lots of desiccant packages. This summer has been brutally humid.
08-23-2018, 01:37 PM   #7
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Thanks for all the advice! I'll take the lens apart and take a closer look when I have time.


You've got me a bit worried now about this fungus spreading, When I bought the camera, it was in a camera bag with another lens attached and a good tight-fitting rear cap on the affected lens. Just did a flashlight test on the other lens and now I'm afraid it might have fungus too! I've been carrying the camera and both lens in my good camera bag—should I disinfect it or something before putting another camera or lens into it?

Don't think I'll be buying any more lenses from the Goodwill auction site!
08-23-2018, 07:14 PM   #8
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To get to the rear element, you have to remove the 5 JIS mount screws. There is an inner black piece that can be removed without any further screws, and be careful because the aperture ring will also slide off. You need to remove the light shield, the inner black ring in your photos. On my parts lens this was on really well, possibly with some thread locker. I'd try some solvent on your lens, but on mine I clamped some locking pliers to the rim and tapped it with a hammer to get it moving. Then you can get to a retainer ring with spanner slots, which holds on the rear element. My lens had no threadlock on the retainer ring.

If you can get that far, I can send you my rear element.

I don't think it's element separation because I don't think this lens has any cemented elements. I'm guessing because I can't find an optical diagram, but the similar Pentax-A 135/2.8 has no cemented elements and is also 4 elements/4 groups.

08-23-2018, 07:37 PM   #9
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To clean and kill the fungus, soak it in a 50/50 solution of hydrogen peroxide and ammonia. Check out these articles:

Fungus: how to prevent growth and remove it from optical components

How to Remove Fungus from a Lens
08-24-2018, 04:54 AM   #10
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I removed fungus with peroxide three years ago. And no problem at all. Without special skills or tools.
08-26-2018, 06:02 PM   #11
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QuoteOriginally posted by maxs Quote
I removed fungus with peroxide three years ago. And no problem at all. Without special skills or tools.
I even used Windex on one. Worked so well, I've been wondering why I don't use it more often.
08-27-2018, 05:26 AM - 1 Like   #12
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QuoteOriginally posted by clickclick Quote
I even used Windex on one. Worked so well, I've been wondering why I don't use it more often.
Yes, is only fungus, not Chuck Norris. Can´t survive everything :-)
08-30-2018, 11:40 AM   #13
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Thank you all for the replies and advice! I'll take the lens apart when I have some time and give cleaning it a go. Just1MoreDave, will let you know if I need the rear element. Thanks so much!
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