2x converter...

Discussion in 'Photography Equipment & Products' started by Deadeye008, Jul 12, 2007.

  1. Deadeye008

    Deadeye008 TPF Noob!

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    Does anyone know of a 2x tele converter that will allow me to still use AF with my Canon EF 100-300 f/4.5-5.6 USM? All the ones that I've seen say that the AF only works on lenses with a max aperature of f/4. Any help or suggestions are appreciated. Thanks.
     
  2. lostprophet

    lostprophet No longer a newbie, moving up!

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    there is no such converter which will work very well, the Kenko/Teleplus might AF if there is a lot of light but it will probably be very slow
     
  3. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    It's not the converter that is the limiting factor...it's the AF system of the camera.

    Most camera's AF sensors need at least the equivalent of F5.6 to focus properly. Teleconverters 'steal' light...and a 2X converter will steal about two stops of light. So that would mean that if you use it with an F4.5 - 5.6 lens...the camera is only getting F9 to F11...not enough for the AF to work.

    So even with an F4 lens...a 2X converter might still not allow for AF.
     
  4. sabbath999

    sabbath999 No longer a newbie, moving up!

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    1.4's generally "steal" less light, but again you are getting pretty dim if you are starting out with a 5.6
     
  5. Jon, The Elder

    Jon, The Elder TPF Noob!

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    What are you shooting? Are you just looking for a less expensive way to increase range?

    There are some tradeoffs in TC's that don't always work with certain styles of shooting. If you know any 'birders', check with them.
     
  6. Deadeye008

    Deadeye008 TPF Noob!

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    I would be using it to shoot wildlife. I would just like a little more range than 300mm. I've also been looking at the super telephoto mirror lenses but have found mixed reviews on them...
     

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