I first rented the 100-400 lens about 4 years ago for rugby. Really fell in love with the lens. Kept hearing about the new lens that was "about to be released" so I waited. I have waited for so many years I am pretty sure if the price is a typical Canon price then I will just drop this as a must lens for me. I will have to try out the tamron 150-600 instead. I am not a pro, so if I get a decent quality build I would be fine with the images that I have seen released. I know tons of professionals never buy non Canon lenses for their cameras. Maybe canon is fine with that, with their current price structure however they will miss out on a large market for their lenses.
Good post. A year ago I would have lined up to spend 2K'ish on the alleged 100-400 L replacement. Maybe I would have gotten better IQ than on the old one which I sold but I'd still be limited to 400mm for bird shots and would still be shooting only ducks and herons
So I took a chance on the Tamzooka by preordering. It wasn't to save $$ really. I have thousands of shots I never would have gotten before. At 400mm, even 500, my subjective eval says....it's a tie w/the old Canon 100-400. Now that I can shoot smaller birds, I'm at 600mm most of the time, and yes, I keep it on F8, need to bump up my ISO to 800 or 1250 depending on light. I have no problems w/autofocus, etc
I realize that the 100-400 is used for subjects other than birds...eg sports, other wildlife etc and that a real sharp one might be worth paying double the cost of the Tamzooka. The only thing I would pay a premium for is
compactness...someone comes out w/a D.O. lens in the 200 500 range...that doesnt weigh a ton. Of course, judging by the cost of the 400 DO, it would cost more than a BMW>>>>>