Help: 7D & 1.4 Extender

[TheNissanMan]

I'm standing in Jessops considering a 1.4, would the 7D autofocus with. a 100-400L and 1.4 extenders?

 

[EdBray]

Nope, not with a Canon one. Some of the aftermarket ones will AF if they do not report but it is usually slower and will not always get a lock.

 

[artyman]

No, as 5.6 is the limit and that takes you to f8, there is the tape pin trick, but not reliable and also slower. Manual focusing isn't that hard I do it with both 1.4 and 2X on my Sigma 150-500.

 

[Roy C]

It will AF in live view which uses the image sensor and contrast detect AF as opposed to the normal Phase AF. Trouble is the live view AF is slower than normal.
The new Kenko pro 1.4 tc will AF and give the correct EXIF data (560mm f8) but not sure how good it will be with the 100-400.