What happened to these CPL filters? Is it reversible? Can they be cleaned or fixed? The damage looks like it is inside the glass. I'm concerned it's fungus or something else.

My father bought them around 2014. I’m a beginner, and never used them.

Here’s a clip of the filter

screenshot 1

screenshot 2


1 Answer 1


Polarizing filters are made up of several layers. Since the problem looks like it's "inside" the glass, the layers are probably separating (delamination).

Trying to repair the filter would cost more than just replacing it.

  • \$\begingroup\$ Or one (or more) of the coatings has failed. It's common for CPL's to have 10+ coatings \$\endgroup\$ Jun 14, 2021 at 13:02
  • \$\begingroup\$ @spikey_richie OP states that it looks like it's "inside" the glass. Coatings are usually on the surface. \$\endgroup\$
    – xiota
    Jun 14, 2021 at 23:53

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