I really enjoy K&F filters for a lot of reasons. They're nicely priced, the quality is good, and there's a nice selection of effects you can select from. This 1/4 black diffusion strikes a nice balance between clean, crisp images and a slightly softer look. The marketing material calls it "dreamy" but in reality its just pulling back a little of the clinical sharpness in the modern lens. Your models will thank you and more than likely your retouching will be a little less time consuming. These also bring a little softness and character to your shots.

Construction is good, as expected and I didn't notice any optical imperfections in the glass. I didn't do much of a water proof test to be honest but a little mist was easily wiped away. The packaging was nice, the case is sorta cheap.

I included a couple of sample images in my review. One with the standard UV filter and the second with the Diffusion filter. The details are lost a little uploading the images but when looking at them both you can see the slightly softer look.

I enjoyed using this and I am planning to keep it in my bag for portraits and other possible uses. Easy option to recommend for a softer look.