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Teleconverters

Discussion in 'Pentax Chat' started by Baarca, Oct 17, 2001.

  1. Baarca

    Baarca New Member

    Has anyone used teleconverters on a Pentax MZ-7. If so which type of teleconverter did you use and how did the results turn out. I have thought about getting a 2x converter in order to reduce the amount of lenses that I was carrying.

    Thanks
     
  2. Reading

    Reading Well-Known Member

    Pentax themselves only make 1.4* and 1.7* converters. I think only one variant of the 1.7* is AF and then it is AF with a twist. Rather than pass the AF along to the lens attached, the converter itself focusses the image. This means that if you had you lens set to focus at minimum distance, you could not focus to infinity. However, this does alow for closer focussing than the lens would normally allow!

    I think the Sigma 2* EX converter is reckoned to be pretty good, and will pass the AF along to the lens so that all works as normal apart from a longer focal length.

    Be aware though that any teleconverter loses sharpness and light.

    For a 2* converter, which loses 2 stops of light, an F5.6 lens for exaple may not autofocus as it will effectively become an F11 lens. Many autofocus systems need F8 or below to work. An F4.5 lens may be OK providing the MZ-7 will AF for F8.

    A 1.4* converter may be more workable as it only loses one stop of light.
     
  3. TimF

    TimF With as stony a stare as ever Lord Reith could hav

    Many autofocus systems need F8 or below to work.

    As far as I know, only Canon's EOS-1v and EOS-3 will AF at f/8, and then only on the central point. All others must have f/5.6 or faster.

    Putting a converter on a consumer standard zoom will give rather inferior results. Some of these are on the edge quality wise anyway, and introducing another element won't do them any favours. At the very least, you'd be wise to stick to a 1.4x

    Get out and get shooting!!
     
  4. Pen-Man

    Pen-Man Well-Known Member

    The Teleplus X 2, 7 element converter is just about as goog as any. You may lose autofocus on slower lenses though.

    Keep rocking
     
  5. TimF

    TimF With as stony a stare as ever Lord Reith could hav

    The converter may be excellent, but conventional wisdom is still that zooms (except pro spec ones) and converters don't mix very well./img/wwwthreads/smile.gif


    Get out and get shooting!!
     

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