Does anyone use this combo?

[eightball]

Well my wife bought me the Canon 5D MkIII for my birthday, just getting use to the new button arrangement from the 70D.

Question I was thinking of getting the Canon Extender EF 1.4X III to use with my 100-400 push pull lens. Does anyone use this set up: 5D MKIII + Canon Extender EF 1.4X III + Canon 100-400 lens. If so do you like it and is it worth getting the extender ?

I just read about the Firmware upgrade for the 5D MKIII to version 1.3.3 and it is suppose to allow cross-type autofocusing with the center AF point when the maximum aperture becomes as small as f/8. The information show compatible with the 100-400.

[samophoto]

I have used the 5DIII with 100 - 400 & a 1.4II teleconverter; it will auto focus at f8 using the center point, but very slowly.  I have some very good shots, but more misses then hits.  Suggest you try to rent one for a day and give it a try.
I had better success with the lens and teleconverter with my old EOS 1V (film), knowing what I know now i probably would not invest in the teleconverter.

[eightball]

Thanks for the info.Sam, it dounds like a good idea to rent before buy, thanks.

[Midnight Mover]

Great info, thanks guys