Polariser (CPL)
Polarisatiefilter (CPL) · Lens & optics
A rotating filter that blocks polarised light. Reduces reflections on water and glass, and deepens blue skies.
The effect varies with the rotation angle. Maximum effect at 90 degrees to the sun: a blue sky darker than software can recreate. On water or glass, reflections disappear so completely that you see through to the bottom or behind the window. Light loss: about 1 to 2 stops. On ultra-wide lenses (below 24mm on full-frame), polarisation can run unevenly across the frame and produce banding in the sky. It does not work on metal reflections. Stacking a CPL with an ND is possible, but watch for vignetting.
Tools that help with this: