Sigma 30mm f/1.4 back focus issues

Discussion in 'Photography Equipment & Products' started by gl600, Jan 30, 2010.

  1. gl600

    gl600 TPF Noob!

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    Hey,
    I just bought a new Sigma 30mm f/1.4 lens and it has some significant back focusing going on. :(
    Should I send it back and get a new one or send it to Sigma to get calibrated? (would Sigma charge for that?)
    What are your experiences with getting a new lens that either front or back focuses?
    Thanks
     
  2. Overread

    Overread has a hat around here somewhere Staff Member Supporting Member

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    Sending it in for calibation/correction whilst its still under warrenty would be the best option. I know that canon and nikon will do camera lens calibrations but I am unsure about sigma. Also for camera lens calibration you also have to send your camera in as well (since like lenses cameras also have slight differences in manufacture - which is why sometimes a lens which is soft or has focus issues on one camera can have no such problem on another camera body of the same make)
     
  3. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    I've got that lens and mine also has some focus issues. I've thought about sending it in...but Sigma doesn't have a Canadian service centre and instead refers us to some other company.
     
  4. giorgio

    giorgio TPF Noob!

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    Hi 'all

    Sorry, but, what exactly is back of front focusing?
     
  5. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    It's when the accuracy of the Autofocus is off. If it's front focusing, the actual point of focus will be closer to the camera than the spot that you focused on.
    For example, if you put the AF sensor point on a person's eye and use the AF, you would expect the eye to the sharpest part of the photo, especially if you are using a shallow DOF. But if the lens is front focusing, then the nose might be sharper than the eye.
     
  6. giorgio

    giorgio TPF Noob!

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    I see.., it would be good to test my lenses.

    Thanks
     
  7. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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