enter image description hereThis is a Nikkor 1.8 50mm Which seems to have fungus inside the glass. How do you disassemble this part to clean from the inside?

  • \$\begingroup\$ Did you try to kill the fungus with a UV lamp? Then you could leave the lens for some time in a warm dry environment and later see if you can shake it off without opening it. \$\endgroup\$
    – FluidCode
    Commented May 13 at 15:10
  • \$\begingroup\$ Is that possible? From what I gathered, sunlight was the best way to kill the fungus, but it wouldn't be removed. \$\endgroup\$ Commented May 14 at 0:13
  • \$\begingroup\$ Are you sure that is even fungus? It looks more like balsam separation to me. \$\endgroup\$
    – Michael C
    Commented May 15 at 1:46
  • \$\begingroup\$ I hadn't thought that, but maybe you're right. How can I tell the difference? \$\endgroup\$ Commented May 16 at 14:12

1 Answer 1


assuming this is the same lens (I think it is) https://high5cameras.com/all-articles/repair/nikon-50mm-repair-guide/

the unfortunate line from the linked guide however is:"If the fungus is between lenses in the front group it’s a write off. The front group is a sealed group and cannot be disassembled."

If it were my lens, other than finding a donor with irreparable damage elsewhere, I'd work on the basis that they were able to put it together so it must be possible to take it apart, albeit maybe destructively. I'd be trying some combination of heat, and prying anywhere that looks like it might be where 2 parts are fitted together, based on assuming retaining ring for at least one side is probably an interference fit or glued in place. Of course there's a real risk of completely destroying it in the process, so only attempt if nobody else has a better suggestion, and you don't care about losing the lens.

  • \$\begingroup\$ Thank you very much for your reply. I will try to find a compatible donor 😅 \$\endgroup\$ Commented May 13 at 6:17
  • 3
    \$\begingroup\$ If it's a cemented achromat (implied by the quote in the answer), the glue is stronger than the glass, and very thin so you'll never dissolve it. You could try putting it in cold water and bringing it to the boil. Some optical adhesives are designed to be removed this way, others may also have the same property \$\endgroup\$
    – Chris H
    Commented May 13 at 10:44
  • \$\begingroup\$ I don't know if I have the guts to do that 😅 Anyway thanks for the tip \$\endgroup\$ Commented May 13 at 17:44

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