The polarizing filter is one of the most frequently used filters in photography. Polarizing filters only allow light of a certain oscillation plane to pass through, filtering out all other light rays. This results in a reduction of reflections on glass and water surfaces or paints. At the same time, polarizing filters increase color saturation and enhance contrast. Objects located behind glass, such as shop windows and car windows, become visible again. In landscape photography, the polarizing filter achieves its maximum effect at a shooting angle of 90 degrees to the sun. For an even effect in the picture, the focal length should not be less than 35 or 28 mm in 35 mm format due to the uneven polarization of the sky light.

Circular and linear polarizing filters work on the same principle. Optical gratings on the filter ensure that only linear light waves whose orientation corresponds to that of the grating reach the lens. Unlike a linear polarizing filter, the circular polarizing filter has an additional Lambda/4 plate. This plate is responsible for breaking down the linear light rays produced in the polarizing filter into all components, which are at an angle of 90 degrees to each other, with one component delayed by a quarter wavelength. Thus, all polarization directions are again present behind the filter, eliminating the autofocus problems often caused by polarizing filters.

The circular polarizing filter has excellent optical properties. The multi-coated, high-quality glass lens is embedded in a precisely manufactured metal frame. The rotating filter operates smoothly and stops at the desired setting. It is transported in a protective cover that shields the filter from harmful UV radiation, significantly increasing its service life.