Use a Circular Polarising filter to enhance your landscape photos
By placing a polarising filter in front of the camera lens you can darken the sky, manage reflections, or remove glare from the surface of lakes or the ocean. The rotational orientation of the filter is adjusted to achieve the preferred artistic effect, and increase image clarity.
For modern cameras, a circular polariser (CPL) is typically used rather than a linear polariser. A circular polariser comprises a linear polariser which performs the artistic function, followed by a quarter-wave plate which further transforms the now-linearly polarized light into circularly-polarised light before entering the camera. This additional step avoids problems with auto-focus and light-metering sensors in some cameras, which otherwise may not function reliably with a simple linear polariser.