The polarizing filter is one of the most commonly used filters in photography. Polarizing filters only allow light of a certain vibrational 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 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 a uniform 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 according to the same principle. Optical gratings on the filter ensure that only linear light waves whose orientation matches that of the grating reach the lens. In contrast to a linear polarizing filter, the circular polarizing filter has an additional Lambda/4 plate. This plate is responsible for splitting the linear light rays created in the polarizing filter back into all of their components and placing them 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. As a result, the autofocus problems often caused by polarizing filters do not occur with circular polarizing filters.

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