Consensus on 24-70/2.8 II field curvature at infinity focus?

Benedict Slotte wrote:

My lens has field curvature, with soft edges as a result focused at infinity.

And the “cure” is to focus beyond the infinity mark. For a start, focus using live view, aperture set at 8, place the focus point in one of the far edges, stop down and manual focus until the edge is sharp. You will by trial and error find the “magic focus point” that will bring both the center and edge/corners pin sharp.

This is what I tried to achieve too - using somewhat offset microadjustment. However, I was unsuccessful at getting a sharp center at the same time. Tweaking focus using live view across the frame is of course possible, but kind of annoying.

Another copy I tried was sharp as a knife both in the center and at the right edge, but mushy on the entire left side... There is just a lot of variation going on between copies. The excellent AF of the 1D X just makes any such inconsistencies even more obvious.

It seems to me that the 24-70 L II is not really such a good landscape lens after all.

I suspect you are right and I rather doubt Canon did design this lens with landscape photographers primarily in mind. I know that the original brief for the original 24-70/2.8L and its 28-70/2.8 predecessor was to produce a fast zoom for photojournalist use and I doubt that brief has changed significantly with the MkII. As such some field curvature at infinity would probably be considered a reasonable trade off against other performance characteristics that a photojournalist might consider more important.

I'm certainly not implying this is the case with you but I fear some photographers do buy lenses because they are the fastest or most expensive, rather than with a realistic assessment of what they are actually going to use the lens for, and so can end up making expensive mistakes, perhaps like this. It would be nice if a manufacturer could list all the things a lens is not so good at but naive and unrealistic to expect that of course.  In the meantime we rely on test reviews and hope the reviewer is able to cover the aspect we are particularly interested in.