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Gatorengineer64
Joined: 26 Oct 2017 Posts: 283
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Posted: Sat Jul 03, 2021 11:13 pm Post subject: How common is fungus between cemented elements? |
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Gatorengineer64 wrote:
Was cleaning a lens today, and the first time I ran into fungus between cemented elements. Is this very common? _________________ A7R4, GFX50R and a bucket of mflenses |
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Lightshow
Joined: 04 Nov 2011 Posts: 3666 Location: Calgary
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Posted: Sat Jul 03, 2021 11:39 pm Post subject: |
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Lightshow wrote:
Not super common, maybe 10% but probably less of fungus cases will effect the doublet's common surfaces, I'm not sure if the balsam is food for the fungus, I don't think the new UV curing glues will be a food source, I've not had many lenses infected, and those that were were newly infested or lightly infested, and usually the first inner surface from the end.
The moment you discover fungus you should expose the glass to UV light to kill the fungus. _________________ A Manual Focus Junky...
One photographers junk lens is an artists favorite tool.
My lens list
http://www.flickr.com/photos/lightshow-photography/
Last edited by Lightshow on Tue Jul 06, 2021 9:48 am; edited 1 time in total |
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marcusBMG
Joined: 07 Dec 2012 Posts: 1312 Location: Conwy N Wales
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Posted: Sun Jul 04, 2021 11:38 am Post subject: |
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marcusBMG wrote:
Every time I have had haze/similar of a doublet I have attributed it to cement deterioration, not fungus. It seems most unlikely to me that spores could have penetrated the cement.
Perhaps you could post a pic - tendrils creeping in from the edge would be quite convincing... _________________ pentax ME super (retired)
Pentax K3-ii; pentax K-S2; Samsung NX 20; Lumix G1 + adapters;
Adaptall collection (proliferating!) inc 200-500mm 31A, 300mm f2.8, 400mm f4.
Primes: takumar 55mm; smc 28mm, 50mm; kino/komine 28mm f2's, helios 58mm, Tamron Nestar 400mm, novoflex 400mm, Vivitar 135mm close focus, 105mm macro; Jupiter 11A; CZJ 135mm.
A classic zoom or two: VS1 (komine), Kiron Zoomlock... |
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Zamo
Joined: 08 Feb 2019 Posts: 168
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Posted: Mon Jul 05, 2021 8:54 am Post subject: |
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Zamo wrote:
I have a Jena Pancolar 50 1.8 with a few tendrils, and they are in the cemented part, between glasses. Growing from the sides to the center. Fortunately, they are quite small so I don't really notice them in the pictures. I gave it a nice sun bath, hopefully that killed them (although I expose it to the sun every few months: easy and for free). |
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Gatorengineer64
Joined: 26 Oct 2017 Posts: 283
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Posted: Mon Jul 05, 2021 11:46 am Post subject: |
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Gatorengineer64 wrote:
Unfortunately I reassembled the lens. I guess it could be cement deterioration, but normal delamination is the fernleaf patter commonly seen on old binos.....
I wanted a gauge on this as I buy more old glass for cleaning and repair, I think I will keep in mind that there is a say a 10-20 percent chance its something not cleanable..... Thanks _________________ A7R4, GFX50R and a bucket of mflenses |
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Lightshow
Joined: 04 Nov 2011 Posts: 3666 Location: Calgary
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Posted: Tue Jul 06, 2021 9:46 am Post subject: |
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Lightshow wrote:
Discriptions/pictures will be your best tool to avoid the worst ones, new fungus is fairly wispy, you really have to look for it, so the average seller may miss it. _________________ A Manual Focus Junky...
One photographers junk lens is an artists favorite tool.
My lens list
http://www.flickr.com/photos/lightshow-photography/ |
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Lightshow
Joined: 04 Nov 2011 Posts: 3666 Location: Calgary
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Posted: Tue Jul 06, 2021 9:54 am Post subject: |
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Lightshow wrote:
marcusBMG wrote: |
Every time I have had haze/similar of a doublet I have attributed it to cement deterioration, not fungus. It seems most unlikely to me that spores could have penetrated the cement.
Perhaps you could post a pic - tendrils creeping in from the edge would be quite convincing... |
The spores won't penetrate anything unless there is an opening, the fungus can and will penetrate solid rock, so balsam will be easy in comparison.
https://en.m.wikipedia.org/wiki/Lens_fungus
https://www.sciencemag.org/news/2016/03/iron-eating-fungus-disintegrates-rocks-acid-and-cellular-knives _________________ A Manual Focus Junky...
One photographers junk lens is an artists favorite tool.
My lens list
http://www.flickr.com/photos/lightshow-photography/ |
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