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Thread: Is this a sign of "back focus" lens?

  1. #1

    Default Is this a sign of "back focus" lens?

    hi all,

    i've noticed something which is bothering me, i'm not sure if my lens has "back focus". i've posted some pics. could u guys help me to check pls?

    in theory, DOF covers a zone of 1/3 in front of the focus point and 2/3 behind the focus point. so with this in mind, i began to shoot some figurines that i have at home.

    here are pics that i shot with the first lens at different focus point.

    focus on center


    focus on the right


    here are pics that i shot with another lens. it seems that this lens has back focus is it? or am i wrong? i'm very puzzled.

    focus on the right


    focus on center



    pls advise. is my second lens having some problems? tks!

  2. #2

    Default Re: Is this a sign of "back focus" lens?

    use a focus chart for more accurate test

  3. #3
    Moderator daredevil123's Avatar
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    Default Re: Is this a sign of "back focus" lens?

    Quote Originally Posted by wdEvA View Post
    use a focus chart for more accurate test
    Download the focus test chart here: http://focustestchart.com/focus21.pdf

    Follow the instructions.

    Do note:

    1. Use a tripod. No handholding.
    2, Be mindful of the MFD (minimum focusing distance) of each lens and make sure the chart is beyond MFD.

    BTW... I have Del Piero.. And he is often my subject for lens tests too.
    Last edited by daredevil123; 6th May 2010 at 09:04 AM.

  4. #4

    Default Re: Is this a sign of "back focus" lens?

    ooo i have that chart too. but to put it at 45 degrees exactly might be difficult. i'll try it out tmr. tks. coz as u can see in the pics, it seems that it has back focus, thats worrying me.

    haha oo u got that figurine too? LOL! i havent touch them for a loooong time, been in my drawer for many years. finally took it out to test my focusing lolx.

    wow this is the first time only one reply after one full day LOL!

  5. #5
    Moderator daredevil123's Avatar
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    Default Re: Is this a sign of "back focus" lens?

    Quote Originally Posted by kenny888 View Post
    ooo i have that chart too. but to put it at 45 degrees exactly might be difficult. i'll try it out tmr. tks. coz as u can see in the pics, it seems that it has back focus, thats worrying me.

    haha oo u got that figurine too? LOL! i havent touch them for a loooong time, been in my drawer for many years. finally took it out to test my focusing lolx.

    wow this is the first time only one reply after one full day LOL!
    Don't have to be exactly 45deg la. Agar Agar.

  6. #6

    Default Re: Is this a sign of "back focus" lens?

    if in doubt and have time, send the lens to the service center for testing.
    You wont see me much less remember me but i am the guy who makes you look good.

  7. #7
    Member zk-diq's Avatar
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    Default Re: Is this a sign of "back focus" lens?

    You may use a lens test chart to do your own testing and know your equipment better.
    ie resolution/coma/colour fridge

  8. #8

    Default Re: Is this a sign of "back focus" lens?

    Quote Originally Posted by daredevil123 View Post
    Don't have to be exactly 45deg la. Agar Agar.
    LOL!!!!!!!!!!!!!!! okie!

  9. #9

    Default Re: Is this a sign of "back focus" lens?

    okiee i'll update u all when i'm done with my testing on the focus chart.

  10. #10
    Member dingaroo's Avatar
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    Default Re: Is this a sign of "back focus" lens?

    Any news on your testing?
    A picture a day keeps the blues away!

  11. #11

    Default Re: Is this a sign of "back focus" lens?

    the last second pic is actually FOCUS ON THE MIDDLE. but end up the left object is pretty clear too. i type wrongly.

    past two days wasnt really at home. outside with some events. finally have some free time lolx. okie i'll update all tmr.

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