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Home lens tests for softness

  • 17-07-2006 10:26pm
    #1
    311
    Closed Accounts Posts: 5,332 ✭✭✭


    Has anyone a simple way to test a lens at home to check for distortions.
    I'm happy with the lenses I have ,but I can't help wondering what all the hullabaloo is about lenses having certain problems.

    Was just wondering if there is a way to know if a lens needs to be serviced or needs some TLC.

    Brian.


Comments

  • #2
    andy1249
    Registered Users, Registered Users 2 Posts: 1,403 ✭✭✭andy1249


    Yes , its easy enough to do , if you have access , get yourself a proper " Target" , this is basically a board with a sort of test card pattern on it , you set up the camera with a tripod at the recommended distance and take a picture of it , then examine the picture ,
    The patterns are such that any distortion shows in the patterns.

    If you dont have a proper target then make one , easiest one is a large sheet of white paper and a black marker , and construct a grid on it , make sure the marker is good and black against the white.

    The set up the camera so that the grid fills the whole frame and shoot it.

    Examine the image after ward , softness will show as a gradual lack of contrast etc. compared to the actual card , barrel and pincushion distortion will show up immediately as bending of the lines etc.

    Obviously variations on this can be used to check colour etc.

    But anyway , that should be enough to keep you busy ,

    Examples of this type of test can be seen on www.dpreview.com

    Be warned now , that almost all cameras will show some minimal distortion in this type of test as no lens is perfect , ( some come close though ) , have a look at dpreview to get a feel for what is considered acceptable levels of distortion.


  • #3
    311
    Closed Accounts Posts: 5,332 ✭✭✭311


    Thanks andy ,appreciate that.


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