Circular Polarizing Filter
When light is incident on a surface, it is partly reflected. With a slanting incidence of light, it is also more or less polarized provided that the surface is not electrically conductive like glass, plastic or lacquer or is hardly electrically conductive like water (whose conductivity is low relative to that of metals) . The polarization increases with the angle of incidence, reaches a maximum at around 55° and then drops again.
Electrically conductive surfaces, e .g . blank metal, do not cause polarization . If the metal is lacquered or has an insulating coating, polarization arises at the insulating layer, e .g . aluminum which forms a non-conductive aluminum oxide layer at air.
A polarization filter only transmits light oscillating at a specific direction without hindrance; in the case of light oscillating obliquely thereto, only the portion oscillating in this direction; it is therefore attenuated . Light oscillating transversely to the direction of polarization is blocked . Consequently, reflections can be reduced or even fully eliminated at an ideal angle of incidence of around 55° . Conversely, reflections can also be amplified up to twice the brightness, e.g. for more intensive sun reflections on water, using the filter if it is rotated by 90° from the maximum attenuation.
The blue light of the sky reflected e.g. from red roofs, green grass and foliage is polarized . Landscape shots taken with a polarization filter therefore allow the blue tinge to be reduced and thus produce a better color saturation for purer colors . Blue light from the sky can be intensified using a polarization filter rotated into a suitable position (to emphasize white clouds) because it is highly polarized above all in a direction of view of around 90° to the sun .
The Circular Polarization Filter requires 1 .5 f/stops as a correction .
HR Digital CPL super MC
Best optical glass · perfect optical surface quality · multi-coated ·
high polarizing efficiency · color neutral transmission · extremely scratch resistant · liquid and dirt-repellent coated · rugged slim brass ring with front thread · wide-angle compatible
Sizes: 49 / 52 / 55 / 58 / 62 / 67 / 72 / 77 / 82 / 86 / 95 mm
Digital pro CPL MC
Best optical glass · perfect optical surface quality · multi-coated · high polarizing efficiency · color neutral transmission · very scratch resistant · rugged slim ring with front thread · WA compatible
Sizes: 49 / 52 / 55 / 58 / 62 / 67 / 72 / 77 / 82 mm