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Thread: Focusing problem? Or lens problem?

  1. #1
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    Default Focusing problem? Or lens problem?

    Below are some of the pictures that I took using my EOS350D with my EFS 18-55mm lens.


    This image is taken at 55mm, at aperture 5.6


    This image is taken at 55mm, at aperture 36

    As you can see, the words on the paper is really blur. I have heard that the lens produce soft images, but is it this bad?

  2. #2

    Default Re: Focusing problem? Or lens problem?

    Quote Originally Posted by cantaresg View Post
    As you can see
    no, we cant see.

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    Default Re: Focusing problem? Or lens problem?

    are the pictures too small? how can I post a full sized picture without bursting the space?

  4. #4

    Default Re: Focusing problem? Or lens problem?

    Quote Originally Posted by cantaresg View Post
    are the pictures too small? how can I post a full sized picture without bursting the space?
    crop the words and just post the crops.

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    Default Re: Focusing problem? Or lens problem?

    How about this? Sorry that the picture is in chinese.


    This is taken at 55mm, f5.6, 100% cropped


    This is taken at 55mm, f36, 100% cropped

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    Default Re: Focusing problem? Or lens problem?

    Quote Originally Posted by cantaresg View Post
    How about this? Sorry that the picture is in chinese.


    This is taken at 55mm, f5.6, 100% cropped


    This is taken at 55mm, f36, 100% cropped
    try f8... at f5.6 it could be just due to lens softness wide open (I don use canon, so not sure about the kit lens performance ), and at f36 most probably diffraction have made your image super soft..

  7. #7

    Default Re: Focusing problem? Or lens problem?

    hmm....very hard to tell from here. try to take a pic of a ruler. at least that way, we can see if it is softness or focusing problem.

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    Default Re: Focusing problem? Or lens problem?

    use a ruler? How should I take the ruler? aligned towards the camera? or along the length of the paper? I will try to do it on the weekend. Thanks

  9. #9

    Default Re: Focusing problem? Or lens problem?

    Quote Originally Posted by cantaresg View Post
    use a ruler? How should I take the ruler? aligned towards the camera? or along the length of the paper? I will try to do it on the weekend. Thanks
    hmmm...how to describe? like take it skewed. as in the starting part of the ruler is closest to the cam, and the back part is the furthest. then, focus at a particular point (say 15cm). then if 15cm is in focus, but the whole picture is soft, we can conclude it is the softness of yours lens. if the 15cm is not in focused, but rather, the 10cm mark is focused, we can conclude your lens have front focusing problems, aka time to go service center.

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    Default Re: Focusing problem? Or lens problem?

    something like what was described in the back focusing thread? Like what is described here?
    http://www.focustestchart.com/chart.html
    Ok, I'll do it over the weekend. What are the focal lengths and apertures that I should test?

  11. #11

    Default Re: Focusing problem? Or lens problem?

    Quote Originally Posted by cantaresg View Post
    something like what was described in the back focusing thread? Like what is described here?
    http://www.focustestchart.com/chart.html
    Ok, I'll do it over the weekend. What are the focal lengths and apertures that I should test?
    *nod nod*

    do it wide open first to check the focusing issue.focal length, i think 55 would be good. too wide abit hard to take focus chart.

  12. #12

    Default Re: Focusing problem? Or lens problem?

    From you 1st post.. the newspapers are placed on a chair, & both pictures were taken at different distance.. quite difficult to determine problem.

    For a start, it would be best if you could paste the newspaper on the wall and also use a tripod for the camera. What satay16 suggested is also great but might be difficult with the kit lens 'coz it doesn't have a distance scale.

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    Default Re: Focusing problem? Or lens problem?

    Quote Originally Posted by chewraisins View Post
    From you 1st post.. the newspapers are placed on a chair, & both pictures were taken at different distance.. quite difficult to determine problem.

    For a start, it would be best if you could paste the newspaper on the wall and also use a tripod for the camera. What satay16 suggested is also great but might be difficult with the kit lens 'coz it doesn't have a distance scale.
    Hmm. I did not notice that. I think I might have posted the image test for the 70mm at the second picture on the first post. So sorry about that. But the latter 2 images should be correct as I double checked the exif before cropping. The camera was sitting on the tripod, with mirror lock-up enabled and using a cable release to minimise any possible vibrations already. THanks

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