Originally posted by Lloyd_Christmas Perhaps CPL and wide angle shots are not workable unless literally at a right angle to the sun.
That's about it! Scattered light (what makes the sky blue and adds some overall haziness to many photos) is most polarized when viewed at right angles from the direction of the scattering light source. Since a really wide angle lens has a field of view of more than 90 degrees, the images made with it will cover angles with such orthogonal scattering (the most highy polarized) to angles that are directly toward, or opposite to/away from, the light source - the least polarized.
It's just physics / there's no free lunch!
By the way, CPL has nothing to do with it - any polarization filter will show the same effects.