Polarization filter\nThe polarization filter is still one of the filters used most often in photography. This filtering reduces reflections on glass and the surface of water or puddles. At the same time, they increase colour saturation and enhance contrast. Objects behind glass (display cabinets, windscreens) become visible.\nThe polarization filter is the only filter whose effect cannot be achieved afterwards using image editing software. The reflections must be removed when the image is taken. It's not possible to do it after the shot. The CPL filters reflections out, and increases colour saturation and contrast.\n\nGrey filter / ND Filter\nGrey filters, also referred to as ND filters (neutral-density filters), reduce the entire visible light spectrum evenly throughout the entire filter. Colours and contrast are not affected by this.\n\nFilter factor 4 increases the exposure time / aperture size by 2 stops\nFilter factor 8 increases the aperture exposure time / aperture size by 3 stop\nFilter factor 16 increases the exposure time / aperture size by 4 stops