Do you know if this is dust or fungus in the viewfinder? Purchased a used Canon EOS 1N in "mint" condition from eBay recently that had "no fungus" in the description.

A flashlight was shined through the lens mount to take the picture. When simply looking through the viewfinder, it looks quite clean.

Thanks for your help!

Image of the viewfinder [Another view2 A third view

  • \$\begingroup\$ It's impossible to tell the difference between dust and fungus based on the photo you have attached. All of the "spots" are overexposed and completely blown out, revealing no details. \$\endgroup\$
    – Michael C
    Sep 8, 2023 at 10:40
  • \$\begingroup\$ Hi Michael C. Thank you for looking into it and trying to help. I have uploaded some more images with different exposures, but I am not able to get the focus right. See if they help. \$\endgroup\$
    – gss
    Sep 8, 2023 at 13:16

1 Answer 1


Honestly, fungus would have a different pattern. There are multiple spots so if it was fungus they should all start growing at different time because starting the fungi is probabilistic and thus all the spots should be of different sizes. This must be dust because no camera has completely air tight internals.

Additionally, a mirrorless camera can be more susceptible to having dust in viewfinder than DSLR since there are less obstacles between the lens mount and viewfinder internals.


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