Dust in a Canon 100-400 EF IS ll USM

Discussion in 'Canon EOS' started by katsone, Jun 2, 2021.

  1. I just bought a used Canon 100-400 IS ii USM that's in great shape. I see some dust in the lens, but no spots showed up in the initial images I took. Is it worth while to send it to Canon for a cleaning? Does anyone have an idea what that might cost? Thanks for any information.
  2. It is easily fixed. Stop looking at it.

    All lenses have dust inside. It doesn’t matter.

    Really. It doesn’t matter!
    Vincent Peri likes this.
  3. Even if it's cleaned the dust will most likely return with use. It has to be really bad before causing any effect on the results.
    katsone likes this.
  4. It's also a function of where the dust is. The closer to the front, the less likely it is to matter at all.
    katsone likes this.
  5. katsone likes this.
  6. It is near the front! OK, I'm going to chill out over it. Thanks for your input.
  7. Thanks for all your input and wisdom! I'm going to let it lie and not worry about it!
  8. Dust, even bubbles and light scratches, matter a great deal less in actual practice than in the mind of the purchaser.

    It's astounding how much crud can be on and in the lens and still have it work reasonably well in capturing images:

    Here is my (Kilfitt) Zoomar 500mm mirror lens front on:
    3 Lens-front copy.JPG
    That's fungus

    (more detail at

    Zoomar Sport-Reflectar 500mm f/5.6

    but here is a hand-held picture taken with it:
    DOF is very shallow on these mirror lenses - focus is on the dog.
  9. I had mine sent in last summer. Something was showing up in the shots, only listed as "foreign object" on the slip that came back. Over $400.

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