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Thread: inconsistent focus on my 30mm 1.4

  1. #1

    Default inconsistent focus on my 30mm 1.4

    Hi All,

    I have recently acquired a Sigma 30mm 1.4 and was less than satisfied with its performance.

    I face some issues with its inconsistent auto focus accuracy. At near MFD (i.e. 50cm), the focus was spot on. At range more than 3M, it back-focus by quite abit, resulting in OOF images. However, when using Live view, the focus was spot on.

    Thus, I would like to consult fellow CSers on whether its a body issue or lens problem. I did some research but cannot draw a conclusion.

    Thank you everyone.

  2. #2
    Member
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    Oct 2011
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    Default Re: inconsistent focus on my 30mm 1.4

    Send it to the service centre for calibration

  3. #3

    Default

    Take the same object with the same distance on tripod & handheld. If on tripod can spot on then it due to ur shaky hands.

  4. #4

    Default Re: inconsistent focus on my 30mm 1.4

    Quote Originally Posted by SamTac View Post
    Take the same object with the same distance on tripod & handheld. If on tripod can spot on then it due to ur shaky hands.
    I did a test on multiple objects in very good lighting conditions, all of them shows similar result. I doubt its due to to shaky hands.

    I'll do a more comprehensive test when I'm free. Thanks for the reply.

    Cheers.

  5. #5
    Moderator rhino123's Avatar
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    Default Re: inconsistent focus on my 30mm 1.4

    Quote Originally Posted by CanCanTinTin View Post
    I did a test on multiple objects in very good lighting conditions, all of them shows similar result. I doubt its due to to shaky hands.

    I'll do a more comprehensive test when I'm free. Thanks for the reply.

    Cheers.
    If in doubt... always bring your lens to the service center to do a test. They have the equipment readily available and if your lens is covered by warranty, you should get calibration free anyway.
    I am not a photographer, just someone who happened to have a couple of cameras.
    My lousy shots

  6. #6

    Default

    Quote Originally Posted by CanCanTinTin

    I did a test on multiple objects in very good lighting conditions, all of them shows similar result. I doubt its due to to shaky hands.

    I'll do a more comprehensive test when I'm free. Thanks for the reply.

    Cheers.
    For f1.4, a little shake make a diff. Learnt it from sigma service center.

  7. #7

    Default Re: inconsistent focus on my 30mm 1.4

    Quote Originally Posted by SamTac View Post
    For f1.4, a little shake make a diff. Learnt it from sigma service center.
    I am consistently getting the same result. And when I'm about 4M from my subject, I need to -10 micro adjust on my KR to get a in focus picture. at closer range, AF was spot on. Guess Sigma Svc Ctr is my only choice.

    Thank you everyone for your inputs.

    Cheers

  8. #8

    Default Re: inconsistent focus on my 30mm 1.4

    Quote Originally Posted by CanCanTinTin View Post
    I am consistently getting the same result. And when I'm about 4M from my subject, I need to -10 micro adjust on my KR to get a in focus picture. at closer range, AF was spot on. Guess Sigma Svc Ctr is my only choice.

    Thank you everyone for your inputs.

    Cheers
    It's normal. I took a few days to do some intensive tests with my micro adjustment before reaching -7 and from then on its been awesome

  9. #9

    Default Re: inconsistent focus on my 30mm 1.4

    Quote Originally Posted by hawthorne907 View Post
    It's normal. I took a few days to do some intensive tests with my micro adjustment before reaching -7 and from then on its been awesome
    Hahaha.. but I got a more serious problem. when my subject is close, the focus is spot on.. when it's further away, I need a -10.

    I can only use this as a headshot lens at the moment. haha. Otherwise, liveview can overcome the above problem too.

  10. #10
    Senior Member
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    Nov 2008
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    West
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    2,792

    Default Re: inconsistent focus on my 30mm 1.4

    It is not uncommon for this model to focus well at some distances while making a mess of it at others.

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