Polarizing filters test
9. B+W EW KSM C-POL MRC 72 mm
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B+W filters are manufactured by German Schneider Optics and definitely don’t belong to the cheapest ones. They’re covered by hard, thin MRC coatings which protect them against scratches. The respect of photographers, that these filters have, should go hand in hand with the highest quality.
Results of the test
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Red color extinction coefficient: 2.94E-4 - Score: 3.5/4
Green color extinction coefficient: 3.04E-4 - Score: 3.5/4 Blue color extinction coefficient: 9.81E-3 - Score: 1/4 Mean transmission of the whole spectrum: 35.55% - Score: 2.11/3 Score:
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With filter Score:
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Luminance: 18
Score:
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| Edge darkening 3% Score: |
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Without reservation
Score:
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Usage
The ring turns smoothly with an appropriate resistance, you can hear delicate swoosh. The filter is well-made. During the tests there were no major problems with it.
Summary
The most points in the overall ranking (31.4/37.5) and disqualification. The transmission of the polarizer is quite flat in the majority of the visible spectrum. The extinction coefficient of around 0.3/1000 is a very good result. The polarizer becomes transparent in infrared. C1 and C2 graphs indicate that, either there’s no quarter-wave plate, or it was glue at an angle of 0 or 90 degrees against the azimuth of the polarizer. We’re dealing with a very good linear polarizer, although both on the box and on the ring, there’s something totally different written. It’s hard to guess if it’s a huge mistake and oversight from the quality control, or deliberate action. Whatever the reason, this should not have happened. For obvious reasons, the polarizer was omitted in the overall ranking.Filter for tests was lent by Pstryk.pl
