K&F Concept77mm ND4-64 (2-6 Stops) ND Lens Filter Variable & CPL Polarizers Filter 2-in-1, 28 Multi-Coated Polarizing and Neutral Density Camera Lens Filter (Nano-X Series)

First off, the quality of this thing is superb. Even the packaging is fantastic. It also doesn’t cost that much for what you get. You get a great variable nd filter as well as a polarizer. I will say though the polarizer is an okay feature so if you’re looking for a top of the line polarizer, I would suggest something else. It fits perfect no problems and I have experienced little to no vignetting. I bought this because I needed something to make videos darker as my shutter and iso can’t be changed for video purposes. It does just that and it works wonders at its job. It also helps with avoiding fingerprints if you’re prone to accidentally touching the front of the lens.

This filter works fantastically with my D810. Great quality and packaging. Couldn't be happier.

This little thing might be the coolest little piece of kit I've added to my collection so far. It evens fits with the lens hood on. The little tabs make get in the way when installing or removing the lens hood, but it does not completely block it. Just gotta wrap under one tab and then drop down over the other one. This thing is pretty cool, it has stops and knurling for grip on the lens to move the top lens back and forth and the nd stops are labeled. The adjustment part could be tighter so i know that it has been fully adjusted instead of continuously spinning. But that might just be a limitation with the whole design.

Best versatile filter, excelent build, comes with a cool leather pouch for storage

Biggest problem is the resistance on the CPL filter part. When spinning the CPL filter you either really wrench the filter to the lens, or unscrew the filter from the lens. It’s very annoying.CPL: Filter itself works very well, but does not remove as much glare as a stand alone CPL filter.V-ND: Near perfect. No black X mark across images, but there's is a thin dark vignette at edges of photos, gets progressively more noticeable each stop darker. Very easy to remove in post, but worth mentioning.Would like to see an update where you feel the filter click into each V-ND stop so you know you’re perfectly at 2 or 4 stops etc.

Good quality ND. Works good with iPhone.

I tested this out with photos and videos; the results are excellent. The colors were very accurate, and it enabled me to use some fill flash at times without having to go into HSS. I love how a polarizer can help deepen colors and reduce the shine/reflection from objects, such as glass, the sky, and plants, helping to get deeper colors.The only drawback is you can't use it in unison with a lens hood, but I didn't experience any flaring or other issues that would have required me to use it.

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