howiewu wrote in post #17333703
Another thing to keep in mind is that the 400L has a rather long close focus distance, whereas the new 100-400 II has a very short one. A shorter close focus distance may be beneficial in tight spaces, such as a tropical jungle under the canopy.
In primary lowland tropical forest, the canopy can be up to 80 m high. I do not think that MFD will be the problem here . Especially since you can so rarely see the canopy anyway, let alone anything in the canopy, and definitely nothing on the canopy (unless you are looking down on the canopy from a hill or something)!
In general, I have never felt that tropical forests felt like a "tight" space when walking through them (EDIT: OK, maybe tight compared to, e.g. the Serengeti or Yellowstone; but to me, those are the anomalies in that they exceptionally open spaces), except when you go off trail and get tangled up in rattan! In that case, though, again, MFD is not an issue ... freeing yourself without the humiliation of having a friend cut you loose is!