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Polarizing filters test 2015

1 November 2015
Szymon Starczewski

4. B+W KSM HTC-POL MRC

Polarizing filters test 2015 - B+W KSM HTC-POL MRC

Another company with tradition and reputation which has to be defended. In our first test of filters high prices of their products were usually followed by good results but there was one slip-up too. Today we are taking a closer look at 4 filters you can find the current line-up of B+W.


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Results of the test:

Transmission and extinction coefficient

Polarizing filters test 2015 - B+W KSM HTC-POL MRC

  • Red color extinction coefficient: 2.10e-2; Score: 0.5/4
  • Green color extinction coefficient: 4.54e-4; Score: 3.5/4
  • Blue color extinction coefficient: 6.06e-3; Score: 1/4
  • Mean transmission of the whole spectrum: 43.69% Score: 3/3
    Score: 8 / 11 pts
Flares

Polarizing filters test 2015 - B+W KSM HTC-POL MRC
Without filter

Polarizing filters test 2015 - B+W KSM HTC-POL MRC
With filter

Score: 7.125 / 7.5 pts

Scattering

Polarizing filters test 2015 - B+W KSM HTC-POL MRC

  • Luminance: 16.96
    Score: 4.93 / 5 pts
Vignetting
  • Vignetting difference: 2.82%
    Score: 3.99 / 5 pts
Homogeneity

Polarizing filters test 2015 - B+W KSM HTC-POL MRC

  • Without reservation
    Score: 5 / 5 pts

Final score: 29.0 / 37.5 pts (77.3%)

  • Overall ranking: 3rd place
  • Econo-ranking: 16th place

Design, usage and summary

Good, broadband coatings, relatively easy to clean, seem to be the only noticeable difference when you compare this filter to the B+W Circular-Pol E.

Still the spectrum characteristics are quite different than in two previous tests of the B+W filters. The transmission maximum from green to red exceeds 90% for transparent polarization. It is a lot. The average transmission for the whole spectrum on a level of 44% is the highest in the whole test. Still it had to be paid with worse extinction coefficients on the edge of the visible spectrum. The filter becomes transparent in infrared much faster than the B+W Circular-Pol E and the B+W Circular-Pol MRC models, the difference amounting to 70 nm. In return it lets pass through less unwelcome polarization from the short-wave range. A transmission drop of over 5% for blue might make the image a bit warmer.