Patent: EF 100-400 f/4.5-5.6L IS

[mwh1964]

For me the 70-300L has proven itself worthwhile. It's perfectly sharp, IS is four stops, you even get solid background blur and then it's light and much agile than the alternatives. If I need reach I'll put it on a cheap 60D.

 

[Marsu42]

For me the 70-300L has proven itself worthwhile. It's perfectly sharp

No way, it doesn't outresolve either the ff or crop sensors - I'd say it's absolutely "sharp enough", but no comparison to for example the 100L or afaik other very sharp zooms like the 24-70ii or the 70-200is2.