Canon 100-400mm lens focus problem

Discussion in 'Canon' started by Wally, Dec 19, 2009.

  1. Wally

    Wally Guest

    My Canon 100-400mm lens is 7 days old. This morning while autofocusing
    on a bird, it lost focus, started hunting, and then stopped focusing.
    The focus was jammed at the minimum focus position. Manual focus
    wouldn't work either.

    The zoom was at 400mm, and it was on a 40D camera.

    The situation was remedied by zooming in to less than 350mm. Then it
    autofocused again for a moment, but then jammed again in the same
    position. Turning the camera on/off makes no difference.

    After about 20 minutes of tinkering with it, the lens resumed normal
    operation. But a few hours later it jammed again.

    Anybody else have this problem? Is there a remedy?

    The guy at the store where I bought it said to just keep using it till
    it always does it, because it can't be fixed if it is not acting up.
    But I think I will return the damn thing and let Canon deal with this
    intermittent problem.

    Wally, Dec 19, 2009
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  2. Wally

    Ray Fischer Guest

    Yep. Send it back to Canon or get a replacement.

    If you fiddle with it too much you may void the warranty.
    But then he's a salesdroid and it's his job to take your money and
    then make you go away.
    That gets my vote.
    Ray Fischer, Dec 19, 2009
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  3. Wally

    Wally Guest

    The lens was hunting, unable to focus. Then I noticed it wouldn't
    focus on anything, near or far. The focus had stopped at 1.8 meters,
    the minimum focus distance. I tried the manual focus ring and it would
    not shift the focus -- it stayed on 1.8m. (This is a continuous manual
    focus lens -- manual can be used at any time, even when on AF.)

    Then I changed the zoom and that released the stuck focus system,
    until it happened again.

    Wally, Dec 19, 2009
  4. Wally

    Lucas Guest

    Did you try setting the AF-select switch to 6,5m and beyond?
    Lucas, Dec 19, 2009
  5. Wally

    Wally Guest

    No, because the subjects were usually closer than 6.5m.

    Wally, Dec 19, 2009
  6. Wally

    celcius Guest

    I think the minimum distance to focus with that lens is 6m
    celcius, Dec 19, 2009
  7. Wally

    Wally Guest

    Now why would you think a thing like that? It's 1.8m.

    Wally, Dec 19, 2009
  8. Wally

    celcius Guest

    Sorry, Wally
    I must have been elsewhere ;-(
    I tried my lens today and it works fine.
    However, A few weeks ago, I was out taking photos and the same thing
    happened to me. I was trying to take a shot at 200m or so, and I couldn't
    focus. I shut the camera off (5D Mark II) and it was working again.
    Take care,
    celcius, Dec 19, 2009
  9. Wally

    Charles Guest

    Do return it as it has dirt in it or is out of spec, mechanically. It is
    sticking for some reason.
    Charles, Dec 19, 2009
  10. Wally

    SamSez Guest

    If you bought it from somewhere with a good return policy, I would return
    it immediately. If you explain that you could not use the full-time
    manual focus ring -- that it was truly mechanically jammed -- they should
    have no problem sending you a brand new one -- maybe even cross ship the
    replacement [with a hold on your credit card].

    SamSez, Dec 20, 2009
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