Circular Polarizer in Landscape Photography
Circular Polarizing filters are indispensable since they enable photographers to achieve creative, in-camera effects across many different scenes. Whether shooting deserts, oceans, forests, lakes, mountains, or jungles, a landscape photographer will find a reason to use a Circular Polarizer (CPL or CP). Second, the CPL effect needs to be captured in the camera on location. It is incredibly difficult, if not impossible, to reproduce the effects of the CPL in post-production.
A Circular Polarizer works by removing scattered light and only allowing light rays which are traveling in one direction to enter the lens. By filtering out scattered light, a CPL is able to remove glare from water, glass, or wet non-metallic surfaces. Furthermore, it can cut through the haze in the atmosphere enriching the colors of the scene and increasing the contrast, such as deepening the blue in the sky.
Since the filter works by turning it on your lens until polarization is achieved, the majority of Circular Polarizers are screw-in or round in shape.
The Visual Wilderness articles offer guidance on using a Circular Polarizer in various scenarios as well as offer advice on how to approach vignetting or working with uneven polarization.