Throwing this out there for the sake of discussion, but is anybody worried about the performance of this lens?
My thought process is this.
- 4x on a lens does lead to some inherent difficulty in getting an ultra sharp shot throughout focal range
- extended time in between lens generations, including a delay in what was supposed to be the debut date earlier this year, suggests that there might be manufacturing QC issues, or at least difficulty in improving IQ
Canon publishes the MTF curves of this lens as well as the old one, and you can clearly see the curves are better on the new one.
The IS has been modernized, lens coatings are now updated to eliminate reflections off digital sensors, even if IQ wasn't a whole lot better, it has a lot more going for it.
That close MFD means I can put on a 1.4X TC and get some close ups of small creatures, flowers and birds like Hummingbirds that are not so shy.
The major US camera stores have a 30 day return policy, and often longer for Christmas items, so there is no risk except for return shipping cost.
Unlike a body that is obsolete in 2-4 years, this lens will be the current model for 10 years, probably 15.
...have you looked a the MTFs for the 400/5.6?
Not very good are they - yet this is a highly rated little lens even today.
My point is you should not judge a new lens which is not even in the shops yet by its MTF
It's a very popular lens, especially on CR. I used one for a while and had a great fun with it and got some great shots. But as slrgear says about it:Sharpness
The 400mm ƒ/5.6L USM produces sharp results - not tack-sharp, but certainly very good.
which you can see from their "blur tests" http://slrgear.com/reviews/showproduct.php/product/167/cat/10
The more modern white lenses are much more expensive but the best are "tack-sharp", and you can see that from their MTFs. If the 100-400mm II had poor MTFs, I personally wouldn't go near it. But, it does look very good on paper and as TDP says "When all of the lines get crushed into the top of the chart, the lens promises to be amazing."http://www.the-digital-picture.com/Reviews/Canon-EF-100-400mm-f-4.5-5.6-L-IS-II-USM-Lens.aspx