bburns;


I shoot similar bird subjects; Hummingbirds to Bald Eagles w/the 100-400 on a 40D.


The cons, to me, for this lens are; poor bokeh, a little slow for the lighting (cloudy and overcast) during our New England winter days, and every birders' mantra whine....not enough reach. The 1.4x extender is not an option.


But what I really enjoy about this lens is it's flexibility in shooting scenarios, i.e. landscapes, daylight sports; baseball, F1 racing, and surfing, as well as birding.


And I'm quite satisfied w/the IQ when I've used the lens correctly....after a year and a half, I'm still learning the do's and don'ts....guess I'm a little slow.


Here's an example of an HB; hand held, f9, 1/640, ISO 500 at 380mm approximately 20' from the feeder. The very nice bokeh was furnished by an Adobe wall....ignore the bright spot in the lower left, it's cropped out in my final version.





Another example taken approximately 50' from the Cooper's hawk; f/8, 1/800, ISO 200 at 400mm w/only clarity and sharpening in PS.





Same picture enlarged 100% and cropped.





Concerning the 70-200 IS 2.8 lens; I think you would become quickly frustrated w/it's lack of reach (it's only shortcoming) shooting wildlife, unless you're shooting in a zoo or in a wildlife workshop. There is an example of this lens in "Post your best bird shot" gallery....Kestrel.


Finally, IMO, your choice should be between the 100-400 and a prime.


Good luck and enjoy whatever decision you make


Bill