... but it would seem that a high quality lens without TC should be better than a high quality lens with TC (although I realize I would have a 4.0 with a TC vs. 5.6 with the Canons). And advice I have been given to date is "get the longest lens you can - if you're going to have the TC on 90% of the time the lens probably isn't long enough).
3. The cost. At this point, I'm not going to be an avid birder - I'm still a generalist in my photography. So, the $1900 price tag is kind of pushing the envelope. If it was a 120-400 it would be a no brainer (but then it would be $4000 instead of $1900).
... and I agree with you totally
The thing is the 120-300 f/2.8 is not
a birder lens although it can shoot a few birds quite well like the picture
s that I've posted. Also like PeterP
I bought this lens primary for the f/2.8 because I really enjoy the 'bokeh' at those aperture!
Let's for argument sake assume the 400 f/5.6 to be sharper (and probably what I use it the most for - comparison purpose), which technically it's not according to the MTF as compared the 100-400 IS - When I go on a vacation I still leave the 400 f/5.6 behind and took the 120-300 f/2.8 EX instead. This is a shot @ 600mm with a 2x TC at the moment of impact - you can try to manual focus, but I rather not: