Use
The polarization filter is still one of the filters used most often in photography. Polarization filters only let through light within a certain frequency range. All other light is filtered out. 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. For landscape photography, the polarization filter produces the best effect with a shooting angle of 90 degrees to the sun.
Functionality
Circular (CPL) and linear polarization filters work on the same principle. Optical grids on the filter film ensure that only linear light waves that are aligned with the grid reach the lens. Unlike a linear polarization filter, the circular polarization filter has an additional lambda/4 plate. This plate ensures that the linear light beams produced previously in the polarization filter are redistributed to all parts and are at an angle of 90 degrees to each other. At the same time, one part is delayed by a quarter of the wavelength. This means that behind the filter, all polarization directions are back again.
The polarization filter is the only filter whose effect cannot be achieved afterwards using image editing software. Reflections must be removed at the time the image was taken; after that, it's no longer possible.
|
Filter |
When to use |
| CPL |
In situations wehe you don't need to reduce
shutter speed, use CPL tor deuce glare |
| ND4 |
At low light conditions, but with direct
sunlight, for example: Sunreise, Sunset |
| ND8 |
At cloudy dasy / partly cloudy |
| ND16 |
At days with strong sunlight (bright day with no
clouds) |
| ND32 |
At days with very bright conditions. Completly
clear sky and sun at ist highest point |
