I had never thought of using a diffusion filter and a CPL at the same time, normally and unless you use a matte box with a filter holder, stacking several filters on the lens thread is somewhat annoying, but here K&F Concept has solved the problem by integrating the 2 in 1, so that we can have the light-medium diffusion of a 1/4 Black Mist (to "expand" highlights and soften overall contrast, an aesthetic widely used for example in the Peaky Blinders series, where all the lights present this diffusion and softening) and the advantages of the circular polarizer, which allows us to reduce reflections (polarized light) from different angles, depending on how we rotate the filter. This is very useful to eliminate brightness from the sky (achieving denser, more contrasted and darker skies), photographing through glass (since we can eliminate reflections, depending on the angle of the light) and take photos of the sea with much more vivid colors, since it also helps us eliminate surface reflections from the water, being able to see more clearly the water and what is underneath.

I've tested it with a Sony FX3 and a 24-105mm f/4, with a 77mm filter thread, and it behaves exactly like the other filters (Tiffen Pro-Mist and CPL) I have separately.

Keep in mind that the effect of the black mist filter varies depending on the focal length, and at focal lengths shorter than 35mm it won't be as intense, but if we zoom in to 50-70mm the effect will be more intense.

The product comes in high-quality packaging, as is typical for this brand, with a very strong hard case to store the filter, and several vacuum-packed microfiber wipes, ideal for cleaning lenses and filters. The filter itself has excellent build quality, without adding any optical defects to the image.

It's an excellent option for carrying two very practical filters in one, saving weight and space.

The price is unbeatable (currently €33.99, when only a Pro Mist 1/4 can cost three times as much)