I was a little skeptical when a Canon representative told me that the new Canon EF 100-400mm f/4.5-5.6L IS II USM lens ($2,199) is just as good as the EF 70-200mm f/2.8L IS II USM , the best zoom lens of that range we've tested.
Incredibly sharp throughout zoom range; Optically stabilized; Quick focus; 1:3 magnification; Relatively compact
Pricey; Some barrel distortion at 100mm