i used this for a video shoot in bright sunlight, the sun was dipping in and out of the clouds, so normally, this is a problem. With this filter, I was able to slowly adjust to the changing light, without ruining my footage. Watching the footage back, I noticed a very slight change to sharpness, but nothing that anyone would notice. I’ll be using it a lot in the future. This is my first filter and I’m really happy with it.It fit my Sigma Art 50mm 1.4 perfectly! It felt like it was part of the lens. The build quality is so nice, it has a heavy and smooth feel when turning. The markers on the edge are useful too.