K&F CONCEPT Ultra-Low Reflection ND2–400 Variable ND Filter (Nano-X Series)
The latest addition to K&F CONCEPT’s Nano-X series, the 67mm Ultra-Low Reflection ND2–400 Variable ND Filter, promises a major leap forward in optical performance—and it actually delivers. Designed with their new ultra-low reflection technology, this filter drops reflectivity down to a mere 0.1%, making it one of the cleanest, most ghost-free variable NDs I’ve tested for this price point.
Note: K&F CONCEPT sent the Variable ND Filter to review. However, this is a completely independent review. All thoughts about this item are my own.
If you’ve ever battled flare or ghosting when shooting into backlight or reflective environments, this filter makes a noticeable difference. It holds contrast beautifully, even in direct sun, and keeps those washed-out hazy reflections at bay. The AGC optical glass feels premium, and image sharpness holds steady across the full 1–9 stop range.
The new “putter-style” adjustment lever is surprisingly handy—it allows for precise control without smudging the glass, and videographers especially will appreciate how smooth the resistance feels during gradual exposure changes. The stop markings are clearly printed, which is a small detail that makes a big difference in the field.
The 28-layer nano coating isn’t just marketing fluff—it genuinely keeps the glass easy to clean and resists both fingerprints and water spots. After several location shoots, it was wiped clean with no streaking, and there was zero sign of colour shift or cross-polarisation (a common issue with cheaper variable NDs).
The 7.4mm slim frame is another win. I tested it on a Sony 24–70mm and a Tamron 17–28mm, and there was no visible vignetting past about 19mm for stills or 17mm for video—impressive for a filter with this much range.
Pros
Virtually no ghosting or flare, even in backlight
Excellent colour neutrality and clarity
Smooth and precise “putter” lever adjustment
Durable 28-layer nano coating (waterproof, anti-smudge, scratch-resistant)
No vignetting past 19mm on full-frame
Fantastic Solid Cover/holder
Cons
Lever design may not appeal to those used to traditional ring adjustments
Slight resistance shift at the ND400 end (minor, but noticeable for precision users)
No hard stops, so you’ll want to watch carefully to avoid the X-pattern at extremes
I used the K&FCONCEPT ND Filter to create some still life by light painting. Using the ND Filter on ND4 allowed me to capture a 30-second-long exposure to paint the light with a Harlowe Iris LED Light. Settings F/11, 30 seconds.
Failing to find time for a waterfall or seascape, I settled for a water feature in my gardens. I do hope to finally get out and shoot some proper long exposure with this filter.
Occasionally, I did have a colour cast and some bokeh, but I found this extremely hard to replicate, so it could just have been me. It was very bright when I was trying to shoot, which could be reflections from the water. Or perhaps I had not screwed the filter on fully.
Weird colour cast and bokeh?
Final Thoughts
The K&F CONCEPT ND Filter is for photographers and videographers wanting a versatile, high-quality variable ND without stepping into the ultra-premium price bracket. This is a standout option. The ultra-low reflection design genuinely improves contrast and clarity, and the build quality feels solid and professional. Ideal for long exposures, portraits, or video work where precise light control matters.
I really wanted to get out and test this on some long exposure water like the ocean or a waterfall. However, weather has not been great for weeks now and have been unable to get out and about to do further testing.
Rating: 9/10 – A smart, polished upgrade for anyone serious about neutral density control.
