K&F has been making some really fantastic filters lately. The build quality of these devices is excellent. Precision machined brass rings thin enough not to interfere with the image but strong enough to protect your glass. They screw on very easily and the brass prevents unplugging and threading. The optical quality of the glass is excellent. There is no distortion whatsoever and the nebula filter gives your images a very subtle, dreamlike quality. In my opinion something that is really impossible in Photoshop or with digital editing. You get the realism and quality of a real optical effect and these look absolutely gorgeous. Some people may disagree, but I always prefer to do as much as possible in camera to avoid post-processing. And for videos, this is of course a time saver. Applying this subtle fog effect digitally to video is very processor intensive. This is a neat little way to soften facial features a bit for portraits, and I decided to take a portrait of this little guy. You can really see the difference around the eyes that the filter makes, in addition to the fact that it was very bright and this filter helped soften the shadows. This is a 1/4 crap so the effect is very subtle. Don't let the Black Diffusion name confuse you. This filter brightens your images by reducing contrast and softening highlights. It actually brightens the image up a bit, but in a way that doesn't blur. That's the beauty of real optical filters and not digital post-processing effects. This compares to my German filters, which I have paid a lot more money for in the past.