Expounding on the two most recent posts, I agree that the IQ of the 70-200 f/2.8 + 2x is probably not on par with the 100-400 native. So I would ditch the 1D, as Rob suggests, and then buy a 100-400. Then your net cost would only be about $600. Even less out of pocket, and a tremendous pairing with the 40D, I would think.


As a matter of fact, I think I may do that with my next lens purchase. I was seriously leaning towards a macro, but I've been pretty happy with my flower pics, etc., with my 28-135, and I yearn for the focal length that can get after some wildlife. I will also be getting a 1.4x, just in case.


My ultimate goal is to have a 24-105 and a 100-400 to go with my 17-40, and add a 1-series body. That will effectively cover everything from 17-560 with a 1.4x. I will probably do with my 28-135 for now but my next body will hopefully come with a 24-105L kit lens, so I can retire the 28-135. To be most frugal,I don't want to buy that lens by itself.