Sigh. I really had hoped that I could avoid lusting after the 5D Mark IV. After all, my 5D III is a fabulous camera, and when it doesn't produce what I want, the problem is usually, to paraphrase Ansel Adams, the 12 inches behind the viewfinder.
But it is not to be. I am not going to buy one, but I am apparently doomed to want one.
I managed not to get too excited about the higher resolution, but now it's come out that Canon has adopted the Sony strategy of building the analog-to-digital conversion into the chip, resulting in much improved dynamic range.
According to DPReview, it's nearly but not quite ISO-less and comes close to the Nikon 810. And while I haven't yet seen tests of the new 24-105 f/4--my most used lens--Canon has released MTF charts, and they suggest that will be a marked improvement over the one I have.