Hi there,
I want to buy a telelens for bird photography. I own 20D and budget allows me for something like ~1200$. I also have Kenko Pro 300 1.4x TC. The choice is 300/4L IS or 400/5.6L. 400 is the great lens for flight shots, but is missing IS in low light situations. Attaching 1.4x to 400/5.6...