now have 2 lenses with 82mm filter size that I use often for everyday and wide angle photography. So I need an ND filter for them. The K&F Concept 82mm Variable ND2-400 9 stop variable neutral density filter is pretty hefty. Nothing thin or lightweight on this variable ND filter. There is a triangular index marked on the fixed ring and dots on the rotating ring for min to max light reduction scale. Unfortunately, these markings fall at the bottom of my Nikon F mount 24-70mm f/2.8E lens, but it lands on the top on my Nikon Z mount 14-30mm f/4s lens. It would be useful to have this center at the top on both lenses to calibrate the light level changes. With the 9x light reduction, this filter was even able to photograph the recent annular solar eclipse with 2 additional stops under exposure to see the partial ring of fire effect. But for other bright summer days, dialing to 4-6x reduction is mostly what I need for landscape photos. With a tripod and manual exposure settings or small f-stop on aperture priority, I can get the desired rich landscape scenes. Or with manual exposure or slow shutter speed on shutter priority, I can get the misty effects from waterfalls or flowing water ways or blur effects as cars or Ferris wheels in daylight. I've not seen optical issues with this ND filter as I don't thread this over any UV/protective or polarizer filter already on the lens. I always put this ND filter directly onto the lens without anything in between that can cause adverse optical effects which is not the fault of this filter. I don't see any unusual lines, vignetting or aberrations or uneven lighting issues. This is an economical variable ND filter that can cost 2-3 times more to get the less than 1-9 stops performance.