I am using the &F Concept 82mm Black Diffusion 1/4 & Circular Polarizing Filter with my mirrorless camera. I had not previously worked with black diffusion filters, so it was interesting to see the effect produced. I read that diffusion-filter effects are most noticeable at night with light sources in the frame, and this filter’s effects were most noticeable on light sources photographed in low light. I also noticed this filter seems to generate a slight greenish cast in some areas of an image. I was able to easily correct the greenish cast in Lightroom but left the attached photos uncorrected to show the slight greenish cast. This is another great filter from K&F Concept that comes at a reasonable price. I plan to make use of it, but I am rating it 4 stars instead of 5, due to the slight greenish cast.

To test the polarization provided by the filter, I took three photos of swimming pool water with my camera set to ISO 100 and aperture mode (f6.3.) I took the first photo without the filter, a second photo with the filter in place, but rotated to minimize the polarization, followed by a third photo with the filter rotated to maximize polarization. In both photos where the filter was used, the underwater sunlight ripples on the side of the pool seemed to be sharper than the no-filter photo, and both photos were slightly brighter (possibly due to shutter speed changes when using the filter.) Shadows in the second photo (minimal polarization) had a slightly greenish cast relative to both the “no filter” and “maximum polarization” photos.

I then shot two photos indoors of stuffed animal toys, with daylight coming in from a window on the left side of the subjects. The photos were taken using ISO 100 and aperture mode (f4) with the focus point on the nose of the lion. Rotating the filter to change the polarization made little difference as the indoor light had minimal stray lighting for the polarization to remove. The photo with the filter in place had a greenish cast most pronounced in the silvery background. The filter also had a very slight softening affecting in the fur of the animals – more noticeable in the lion than the other two toy animals. The fur on the lion and the bear in the filter photo were also warmer-in-tone than in the no-filter photo.

I then took two more photos showing ceiling LED lights in relatively low light with the camera at ISO 800 and aperture of f5.6. Once again polarization did not come into play, but the diffusion effect was very pronounced for the light sources. There was a slight greenish cast when the filter was used, but this was easy to correct when editing in Lightroom.

One more thing I like about K&F Concept filters is that the filters always come packaged with K&F Concept microfiber cleaning cloths.