I have this as well as the EF 70-200 f2.8L IS. If you do not need the extra reach, I would highly recommend the 70-200 over this lens. Even with a 1.4x tele-extender, the 70-200 is a better lens. It is much faster, and image quality is superior to the 100-400. The 70-200 is probably one of Canon's best L zoom lenses. The 100-400 is a good lens, but it has some limitations, primary it is slow and images are quite as sharp & crisp. But it is still an 'L' lens and is superior to the consumer grade lenses in the same focal length range. - Jeff P. Henderson
oh, cool. I need about 300mm reach, so the 400 is probably a little overkill. I'll look into the 200 with an extender, I hadn't thought of that. Thanks! - Andre Maltais
