| I've been using the Canon 1.4x II TC with my Canon 70-200 f2.8L IS for quite some time. Not as sharp as the lens alone (and certainly not as sharp as the 300mm f4L) but better than acceptable, and contrast is good. I bought a 2X II TC from KEH around 6 months ago and I'm disappointed in it - poor sharpness and contrast. So, if you need to get to 400mm, not the way to go. If you're interested, I'm planning on selling my Canon 300mm f4L (non-IS) to afford to upgrade my 28-135IS to a 24-105L.
Dan |