Enough that I AFMA'd the lens a second time. Still not sharp.
The 7D has a very demanding sensor and with the 70-200 F4 I always felt cheated...the image just wasn't as sharp as I got from my 70-200 2.8 at F2.8. Mind you, the same applies to the 24-105 which also needs to be used at F5.6 to do justice to the 7D sensor.
So far the only lenses I feel are up to what the 7D can produce wide open are the new 24-70II, the 70-200II, the 70-300L, the trusty old 50 F1.4 and of course the new big whites. Even the 100-400 which works very well on the 5DII and 5DIII doesn't quite cut it - close, but it could be better. I am sure there might be other lenses, but these are what I have used in the field.
Interesting and a bit disappointing.
If I happened to take part to a Safari or something like that, I would consider buying a 100-400mm for my 5D classic... or, alternatively, buying a 1.4 extender (II or III) plus a crop body (7D or 60D, new or used): this combo would grant my existing 70-200 F/4 IS a reach of 448mm @ F/5.6, not much different from a 100-400mm on a Full Frame body.
A crop body + extender 1.4 would cost about the same as a 100-400mm here in Italy.
Any other opinions about the combo 7D + 70-200 F/4 IS L + extender 1.4x?
Thanky you in advance!