70-200 2.8 IS lens won't AUTOFOCUS - anyone else had problems?

Discussion in 'Canon EOS' started by david_baird|2, Aug 2, 2006.

  1. Hi all, I've very recently purchased a Canon 70-200 2.8 IS lens and for some reason it isn't autofocusing. It's pointing at nice, clear, contrasty things, and will focus in manule mode, but doesn't focus in auto mode, just makes a pathetic slow attempt then gives up... (This happens on two different SLRs, and doesn't happen when I put on different lenses) Has anyone else had this issue? Am I doing something daft? It is late, I am tired... but this should be very simple....! Thanks for any help you may be able to give... David
     
  2. Is the limiter set to restrict AF distance?
     
  3. Try swtiching the AF "off" then "on" again.
     
  4. The auto focus (AF) speed, AF accuracy and image quality from my 70-200 IS are fantastic. If your AF still farts around after cleaning the lens contacts, then it's time for either (i) service, or (ii) to return it.
     
  5. Check your limiter switch, cycle the AF switch and make sure you are focusing on something farther than the minimum focus distance. If not that? ? ? ? m
     
  6. And if it still doesn't work _after cleaning the lens' contacts_ then send it back. --
     
  7. BTW, let us know how you solved the issue. That way other users can benefit from this thread.
     
  8. I have the non-IS version and it's a little over a year old. On my Rebel XT body, it refuses to autofocus about one in ten times when I first turn the camera on. I had this problem when it was new and don't have any problems with my other two lenses (50 f1.4 & 17-40 f4L). I probably should have returned it but need to use it so often that I'm not willing to go without it. Anyway, I have tried everything -- cycling the AF/MF switch, removing/attaching the lens, power cycling the body, and playing with the manual focus ring. Each of these "solutions" seems to have fixed it at some time but none are reliable. Problem is that I'm usually in a panic when it doesn't work and am trying everything at once (and then I promptly forget about the problem when it starts working). Obviously, I need to do a controlled experiment...
     

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