K&F Concept black diffusion Mist ¼ effect & Variable ND2-400 is the first combination filter I am trying out. At first look, the filter comes in a very nice retail box. Inside the filter is package in another soft storage case. There is a strap that when you pull it will push up the lens out from the storage case. The lens feels solid with a orange turning knob that allows easy turning of the lens. On one lens you can small faint black dots at an angle. I think that give the mist effect on the photo? Overall, I am surprised the lens is made in China. Most of my early filter lens is from Germany or Japan.
The dreaming effect of the lens is interesting. I am learning how to use it. It gives a softer effect but also diffuses the background sun light in an exaggerated effect which often would overtake the subject. The ND filter is good to increase the exposure time. But the filter does not have a hard stop to tell you how much light is restricted. It is great for video since it is stepless, for still photo you will need to play with the setting.
I am new to this combination filter and using it on Nikkor 24-70mm f2.8. At the end of the testing the ND filter, it accidently locked onto my UV filter. I am waiting on the lens wrench to unscrew the filters apart.