Articles

Polarizing filters test

7. B+W Slim C-POL MRC 72 mm

	B+W Slim C-POL MRC 72 mm	Price: 459 PLN

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. Slim polarizers allow us to work with wide-angle lenses without additional vignetting coming from the ring.

Results of the test

Transmission and extinction coefficient
- - - - - - - - - - - - - - - - - advertisement - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Red color extinction coefficient: 6.12E-4 - Score: 3/4 Green color extinction coefficient: 5.86E-4 - Score: 3/4 Blue color extinction coefficient: 2.11E-2 - Score: 0.5/4 Mean transmission of the whole spectrum: 34.57% - Score: 1.91/3 Score:	8.41/15
Flares
Without filter With filter Score:	7.5/7.5
Scattering
Luminance: 16.5 Score:	4.94/5
Vignetting
Edge darkening 3.6% Score:	3.56/5
Homogeneity
Without reservation Score:	5/5
Final score
Overall ranking: 2nd place Econo-ranking: 9th place 29.4/37.5 pts (78.4 %) 0.24 pts

Usage

Cleaning wasn’t too troublesome. The ring turns smoothly with an appropriate resistance. The filter is well-made, it’s impossible to find fault with its construction. We get a cap in the kit.

Summary

2nd place in the overall ranking
The polarizer’s transmission is flat in the majority of visible spectrum. Pictures may have than in reality. The extinction coefficient of around 0.5/1000 is a good result. The polarizer becomes transparent in infrared. Similarly to other products of this brand, we observe slight transmission of blue color, which should be extinguished. C1 and C2 graphs indicate that we’re dealing with a quarter-wave plate of zeroth order designed for the middle of visible spectrum. Vignetting is comparable to the one with a wider ring. The tests were conducted using a camera with a sensor of 1.5 crop factor and the Sigma 17-70/2.8-4.5 lens. You can see, then, that in this configuration the angle of view isn’t wide enough to observe the advantage of slim filters. Taking into account the optical characteristics and the quality of build, it’s hard not to recommend this filter.

Filter for tests was lent by Pstryk.pl