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Thread: IQ loss with tele-converter

  1. #1
    Member Ron Evers's Avatar
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    IQ loss with tele-converter

    I have often read that you loose IQ if you use a tele-converter so I wanted to see for myself. I used a Vivitar series 1, 70-210/3.5 & a Vivitar 2x converter for the experiment on my G1. I set a tripod on our balcony & shot the bird bath in the back yard with a salmon tin sitting in it. The ISO was set @ 100 & I used f5.6 for the shots.


    1. Lens set ~ FL 200, no converter, 1/1600s




    2. Lens set ~ FL 100 with 2x converter to equal FL 200, 1/400s




    There is definitely a loss of light & IQ with the converter in this simple trial.
    Panasonic G1 & GF1 bodies, Panasonic 14-45, 45-200mm, various Minolta, Pentax, Canon FD, M39 & M42 mount lenses.

  2. #2
    Senior Member pellicle's Avatar
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    Re: IQ loss with tele-converter

    are these 100% segments?

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    Senior Member Devon Shaw's Avatar
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    Re: IQ loss with tele-converter

    I've appreciated seeing your tests with all these old lenses.

    One possible problem I see with this test though is that the lens might not have the same image quality when used alone at the different focal lengths.

  4. #4
    Member Ron Evers's Avatar
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    Re: IQ loss with tele-converter

    Quote Originally Posted by pellicle View Post
    are these 100% segments?
    I cropped off snow top & bottom only.
    Panasonic G1 & GF1 bodies, Panasonic 14-45, 45-200mm, various Minolta, Pentax, Canon FD, M39 & M42 mount lenses.

  5. #5
    Member Ron Evers's Avatar
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    Re: IQ loss with tele-converter

    Quote Originally Posted by Devon Shaw View Post
    I've appreciated seeing your tests with all these old lenses.

    One possible problem I see with this test though is that the lens might not have the same image quality when used alone at the different focal lengths.

    I expect this is true of any lens.
    Panasonic G1 & GF1 bodies, Panasonic 14-45, 45-200mm, various Minolta, Pentax, Canon FD, M39 & M42 mount lenses.

  6. #6
    Senior Member pellicle's Avatar
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    Re: IQ loss with tele-converter

    Quote Originally Posted by Ron Evers View Post
    I cropped off snow top & bottom only.
    no wonder it was hard for me to pick any significant difference.

    I'd feel comfortable using that TC .... :-)

  7. #7
    Senior Member Tullio's Avatar
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    Re: IQ loss with tele-converter

    Both images look very similar (you can actually see more details under the water on the second shot). I have a Kenko 1.5x tele-converter (Pentax mount). I'll check it out just out of curiosity.
    Tullio

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