# Question Regarding Auto focus Canon EF 1.4X III



## faz (Mar 11, 2015)

Auto focus Canon EF 1.4X III Telephoto Extender works with Canon EF 100-400mm f/4.5-5.6L IS II USM Lens?

Thanks
F


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## neuroanatomist (Mar 11, 2015)

Yes, with the center point on bodies that support f/8 AF: 7DII, 5DIII and more recent 1-series bodies.


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## Mt Spokane Photography (Mar 11, 2015)

The extender fits and functions fine with the lens. 

However, it does cause the effective aperture to be f/8, so only certain cameras will autofocus at f/8. 

If you have a Rebel or 7D or 60D or 70D, you will not be able to autofocus. There are some taping of contacts tricks that interfere with the communication from lens to camera that will let it autofocus, not totally satisfactory, but much better than none at all.


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## faz (Mar 12, 2015)

My Camera is Canon 7D Mark II do you think Auto-focus will work ?

Advice please


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## AlanF (Mar 12, 2015)

faz said:


> My Camera is Canon 7D Mark II do you think Auto-focus will work ?
> 
> Advice please



It works absolutely beautifully!


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## mackguyver (Mar 12, 2015)

Also, note that all cameras will autofocus using LiveView, even at f/8 or f/11 (for the 2x).


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## Marsu42 (Mar 12, 2015)

mackguyver said:


> Also, note that all cameras will autofocus using LiveView, even at f/8 or f/11 (for the 2x).



Magic Lantern can help there, it's got focus peaking for af confirmation in live view and can boost the display gain when very little light should be available at small apertures and low light.


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## faz (Mar 12, 2015)

Thank you everyone for the help I really appreciate


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