Assuming there is no huge visible fungus, inside, how to verify whether the second hand lens is affected by spores?

It is said that spores don't die and fungus may regrow. Also it is said that if we keep fresh lens with infected lens, fungus will spread.

Assuming it has tiny fungus, will it still spread if I keep it in hygienic conditions?

How to verify whether the invisible/removed fungus in the second hand lens is dangerous?

What are the signs that the white particles inside the lens are just dust and not fungus?

Basically I want to understand how to identify fungus when it doesn't look very obvious.

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  • 2
    \$\begingroup\$ @flolilolilo I want to know when fungus is not easily visible then how to determine the state. This is not a duplicate. \$\endgroup\$ Sep 23, 2018 at 11:52
  • \$\begingroup\$ As visual inspection is the only way of detecting it (without completely disassembling the lens, that is), then if you cannot detect it, there either is no fungus or it cannot be detected. It's as simple as that. \$\endgroup\$
    – flolilo
    Sep 23, 2018 at 11:59
  • \$\begingroup\$ Maybe you can tell me what is the proper way to visually inspect it. @flolilolilo \$\endgroup\$ Sep 23, 2018 at 13:32
  • \$\begingroup\$ I suggest changing the title to focus on the issue if whether invisible or removed fungus is still a threat. The other question should cover visual inspection. \$\endgroup\$
    – mattdm
    Sep 23, 2018 at 13:52

2 Answers 2


Fungal spores are everywhere. Like, everywhere. There are definitely fungal spores in your camera and in your lens, unless maybe you happen to be in a NASA clean room. I mean, not to be gross, but they're on you. The question is if conditions arise for fungus to grow.

Well, the two questions are that, and whether the lens has etching or other damage from a previous fungal growth.

It's true that an active fungal growth gives off more spores, so it's good to keep equipment you know is affected in quarantine. But if it's been killed and the equipment cleaned, it's no worse than anything else.

  • \$\begingroup\$ " lens has etching" what does this mean? \$\endgroup\$ Sep 24, 2018 at 7:32
  • \$\begingroup\$ I'll expand a bit when I get a chance. In short, fungus secretes acid which can eat into coatings and even the glass itself. \$\endgroup\$
    – mattdm
    Sep 24, 2018 at 12:21
  • \$\begingroup\$ Sounds frightening. How to verify whether that is the case in the lens or not? \$\endgroup\$ Sep 24, 2018 at 12:45
  • \$\begingroup\$ See Does the lens I just bought have a fungus? (and some of the other fungus). \$\endgroup\$
    – mattdm
    Sep 24, 2018 at 13:07
  • \$\begingroup\$ All other questions talk about the case when fungus is clearly visible. In that case I simply won't purchase. In the current picture I can see some white dots which can be dust or fungus. What would be the way to verify in such cases? \$\endgroup\$ Sep 24, 2018 at 14:40

How to verify whether the second hand lens is affected by fungus?

Is the lens located pretty much anywhere on planet Earth? Then it is exposed to fungal spores. Whether those spores have had an effect or not can be done by visual inspection.

Insuring that a lens is not negatively affected by fungus is the same for a used lens as for a new lens. Prevent the conditions that allow fungus to flourish inside a lens:

  • Warm temperatures
  • Moisture
  • Lack of UV light (such as unfiltered sunlight)

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