Marks around the edge of a lens front element: fungus, coating damage, or just residue?
Asked 11/8/2025
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2 answers
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I bought a used Vivitar 75-205 and noticed marks around the outer edge of the front element. They appear limited to the rim rather than spread across the whole glass. I'm trying to figure out whether this looks more like fungus, coating damage, or simply residue/smudging. I'm mainly concerned about whether it could spread to other lenses or the camera, and whether I should try cleaning it first.
Originally by madhead. Source · Licensed CC BY-SA 4.0
madhead
7mo ago
2 Answers
2
It is not easy to tell as the images are not very sharp on the surface details.
From the extent of it and the limit to the edges, I would rather think it is either coating defects - or just not really clean. If it is a coating defect, it might be extensive and just the outer rim has not completely stripped.
Also smudge buildup around the edges of the front element is not too rare, so the first thing I would recommend if trying to wet clean the element with a fresh microfiber cloth and Eclipse or ROR lens cleaning fluid.
Pay extra attention to get as close to the edge as possible. You can carefully use a fingernail or a wooden spatula covered with 2 layers of cloth to try to get as close to the rim as you can. Don't press too hard.
If you suspect fungus, you might want to discard the cloth afterwards.
If it is on the inside, or if you see little tendril like structures, then it might be fungus.
Originally by Kai Mattern. Source · Licensed CC BY-SA 4.0
Kai Mattern
7mo ago
0
Generated from our catalog & community — verify before relying on it.
Based on the answer provided, this does not clearly look like fungus from the photos. Because the marks seem confined to the outer edge, it is more likely to be either residue/smudge buildup or a coating defect.
A good first step is to carefully wet-clean the front element using a clean microfiber cloth and proper lens-cleaning fluid. Work gently and get as close to the rim as you safely can without applying much pressure. If the marks come off, it was likely grime or residue. If they remain unchanged, coating damage is more likely.
The answer did not identify it as fungus, so there’s no strong reason from this evidence alone to assume it will contaminate your camera or other lenses. If you still suspect fungus after cleaning, use a fresh cloth and avoid reusing the one that touched the lens.
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UniqueBot
AI7mo ago
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