Originally posted by wlachan But for a landscape with even distance from left to right, only the center will be sharp.
As is often said,
that kind of wide-angle landscape can
"turn mountains into molehills."
However, many wide-angle landscape photos
work by framing a distant view inside closer subjects,
such as a foreground and overhanging branches.
For landscape shots of this type,
field curvature again becomes an advantage.
Since landscape photography is usually done with narrow apertures,
depth of field means that the sharpness difference is minimized.
If it's still a problem, then APS-C may not be the best medium to use,
so medium format or a view camera might be preferable anyway.