Is my lens not working correctly?

Discussion in 'Canon Lenses' started by rwalsh81, Jul 7, 2017.

  1. rwalsh81

    rwalsh81 TPF Noob!

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    As I'm still fairly new this is definitely a noob question. I recently purchased a used canon macro lens specifically the Canon EF 50mm f/2.5 Compact Macro Lens. When I try to take a picture using auto focus the lens just keeps on zooming in and out on me. So far I've only been able to use it while doing manual focus. Is it supposed to do that or did I get a lemon?


     
  2. Designer

    Designer Been spending a lot of time on here!

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    I think macro lenses have difficulty with auto focus. The reason is the the DOF is very thin, so depending on factors such as the camera's focusing engine, DOF, your subject, etc., auto focus will be a problem. Just use manual focus for macro.
     
  3. BrentC

    BrentC Been spending a lot of time on here!

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    This lens has a 9" minimum focus distance. So if you are within 9" of your subject then the lens will not be able to lock in focus but continue trying.
     
  4. rwalsh81

    rwalsh81 TPF Noob!

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    Ok, but if that's the case how can I focus in manually if I'm within the 9"? Like I said I'm a noob.
     
  5. BrentC

    BrentC Been spending a lot of time on here!

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    Do you have enough light?
     
  6. rwalsh81

    rwalsh81 TPF Noob!

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    I believe so, when I get the manual focus up close I can clearly see the subject. Plus the shots have either been outside or at my desk at work which has tremendous lighting.
     
  7. BrentC

    BrentC Been spending a lot of time on here!

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    Have you tried a non-macro shot and it still doesn't auto focus?
     
  8. rwalsh81

    rwalsh81 TPF Noob!

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    With that lens I thought it was just macro. My other lenses auto focus with no problem.


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  9. BrentC

    BrentC Been spending a lot of time on here!

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    It can be used like any other lens. Go outside and take a picture of your car or anything really and see if it auto focuses properly.
     
  10. rwalsh81

    rwalsh81 TPF Noob!

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    Thanks I'll take a look when I get home. Didn't bring the camera with me today.


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  11. Designer

    Designer Been spending a lot of time on here!

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    From the list:
    • Closest focusing distance: 0.8 feet
    Which is 9.6 inches. I presume you already know this, and are not trying to get closer.

    Things to try:

    Choose a different subject. Sometimes the edge/contrast of the subject is marginal for AF.

    Have a small flashlight available to shine light from a slightly different angle onto your subject. (same reason as above)

    Use a tripod. Your natural body movement may be enough to prevent the AF from locking on.

    If none of those help your lens AF, then just resign yourself to focusing manually for macros.
     
  12. petrochemist

    petrochemist No longer a newbie, moving up!

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    Nearly all macro lenses focus right out to infinity. The only exception I can think of is the Canon MP65E which is a very specialist lens.
    AF is not good for macro, where having the focus on slightly the wrong part can make the important bit seriously out of focus. Your lens should easily focus on things a few feet away in good light. If it can't then somethings wrong - unless the switch is just set to MF :).
     
    Last edited: Jul 10, 2017

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