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Thread: what is calibration lens?

  1. #1
    Member tianzhong's Avatar
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    Default what is calibration lens?

    As mention in the thread thread,

    I will like to know what the meaning of calibration lens mean? Pro out there help me?

  2. #2
    Senior Member zac08's Avatar
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    Default Re: what is calibration lens?

    The term should be lens calibration.

    Certain lenses may need to be calibrated to the camera so as to improve the focusing accuracy and speed. Certain issues may plague certain lenss, such as front focusing or back focusing.
    Michael Lim
    My Flickr Site

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    Member tianzhong's Avatar
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    Default Re: what is calibration lens?

    Quote Originally Posted by zac08 View Post
    The term should be lens calibration.

    Certain lenses may need to be calibrated to the camera so as to improve the focusing accuracy and speed. Certain issues may plague certain lenss, such as front focusing or back focusing.
    what if i gt a sigma lens and using a camera body. to calibrat the lens , i should go to canon or sigma?

    I don understand what is having the problem with front focusing or back focusing?
    pleasse advice! thanks for replying!

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    Moderator Octarine's Avatar
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    Default Re: what is calibration lens?

    Quote Originally Posted by tianzhong View Post
    [orange removed... eye sore..]I don understand what is having the problem with front focusing or back focusing?
    Google helps.
    Front or Back focusing is an error in executing the focus command of the body, resulting in a lens being focused on a point slightly in front or slightly behind the actual focus target.
    DSLR with phase detection AF system (standard) calculate the necessary change in the focus lens group and issue a single command to the lens to turn the AF ring. If everything is fine then the lens is perfectly focused on the focus target (defined by the selected AF point(s)). With front focusing the lens is not focused on the target, but on an imaginary point just in front (closer to the camera) of the object. Back focusing is similar, just behind the focus target. Calibration is to remove this 'offset' and bring the lens back on target.
    To test whether a lens suffers from this issue just search for 'focus test chart', read the instructions carefully, get a tripod and test.
    Last edited by Octarine; 2nd September 2010 at 01:42 PM.
    EOS

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    Senior Member sinned79's Avatar
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    Default Re: what is calibration lens?

    Quote Originally Posted by tianzhong View Post
    what if i gt a sigma lens and using a camera body. to calibrat the lens , i should go to canon or sigma?

    sigma of cos.

  6. #6
    Senior Member zac08's Avatar
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    Default Re: what is calibration lens?

    Quote Originally Posted by tianzhong View Post
    what if i gt a sigma lens and using a camera body. to calibrat the lens , i should go to canon or sigma?

    I don understand what is having the problem with front focusing or back focusing?
    pleasse advice! thanks for replying!
    Sigma of course...
    Michael Lim
    My Flickr Site

  7. #7
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    Default Re: what is calibration lens?

    do they tweak the camera electronics too? or lens only?
    i'd like to have my lens calibrated but i'm afraid of something being altered to the camera so i never went in for any calibration yet..

  8. #8
    Senior Member zac08's Avatar
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    Default Re: what is calibration lens?

    Quote Originally Posted by aungzawwin View Post
    do they tweak the camera electronics too? or lens only?
    i'd like to have my lens calibrated but i'm afraid of something being altered to the camera so i never went in for any calibration yet..
    Should be lens only. You can check with them for more info.
    Michael Lim
    My Flickr Site

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