2x converter...

Deadeye008

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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.
 

lostprophet

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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
 

Big Mike

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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.
 

sabbath999

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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
 

Jon, The Elder

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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.
 
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Deadeye008

Deadeye008

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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.

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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