AF speed of 400f5.6 v/s 300f4IS+1.4x on 1DMarkIIn
I love photographing birds and I'm now planning to take this hobby seriously. I currently own 1DMarkIIn and following glass 70-200f2.8IS, 300f4IS, 1.4X Kenko Pro300.
The longest I can get is 300mm*1.4*1.3(1D crop) = 546mm
But, worried about AF speed when using extender for birds in flight. I want my 1D2n to track flying birds at very good AF speed. Should I think of sell 300mm for any other lens?