The K&F Concept Variable ND2-2000 filter is a brilliant and much needed photo accessory if you work a lot with flash or in hard sunlight setups. I had not in the past used ND filters much. But in recent years I have been shooting more and more with fill flash in hard sun lit conditions. As most photographers know, once you sync a flash with your camera the top shutter speed is capped, usually at 1/125 sec. Sometimes even the smallest aperture on a lens isn't small enough to cut the light level down enough. And of course you don't really want the smallest aperture as lens performance usually starts to suffer at smaller apertures. That pretty much guarantees over exposure problems unless you can cut down the light input. In the past you had to carry a variety of ND filters for various stops. But this new variable ND from K&F has a 1-11 stops range. Just amazing. It's like having a second aperture ring. You can just dial down the light volume until the other exposure parameters you care about, histogram, zebra, etc, all align to your liking. Absolutely a great buy if you need what this filter has to offer.