Quote Originally Posted by Richard Lane
because with the 1.4x converter and the 70-200mm 2.8L II the lens maintains "very good" quality up to 280mm f4L

I agree - on nice days I use theEF 100-400mm f/4.5-5.6<span style="color: red;"]LIS for birds and wildlife...but on rainy days, I use theEF 70-200mm f/2.8<span style="color: red;"]LIS II, often with theEF 1.4x II Extender, for a weather-sealed combination with my 7D. The shot below was with the 70-200mm II + 1.4x, early on a spring morning through a heavy, misty drizzle.


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But, the size and weight of the 70-200mm f/4L IS, combined with excellent IQ, make it a very attractive lens!