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Three notations for one quantity, and the box may use any of them

The best ND filters for 2026

A neutral density filter takes light away without changing its colour, so that a shutter can stay open longer or an aperture stay wider than the daylight would otherwise allow. The confusion on this shelf is notation: the same filter may be sold as ND8, as 0.9, or as 3 stops, and the three describe one quantity in three conventions — a factor, a logarithmic density, and a count of halvings. A listing that gives only one of them is not wrong, but a bag with filters labelled in two systems is a bag where the wrong one gets fitted. Variable filters put two polarising layers in one ring and cover a range by rotation; they are convenient, and the honest ones publish where the range stops, because beyond a certain angle they produce a dark cross across the frame that no processing removes. Colour cast is the second quality marker: no filter is perfectly neutral, the deviation grows with strength, and makers who publish a figure or a measured curve are telling you something the photographs on the listing will not. Then the usual: thread size, coatings that resist water and fingerprints on a filter that lives outdoors, and frame thickness on wide lenses. We compare strength and the notations given, fixed or variable construction, thread size, stated colour cast, coatings and frame thickness.

The accessories that earn their place in the bag

  1. K&F Concept variable ND filter with its knurled trapezoid-patterned ring

    K&F CONCEPT 67 mm variable, ND2-400, 1 to 9 stops, 7.4 mm

    One to nine stops on a variable 67 mm filter for 29 €, in Japanese AGC glass — from a page that tells you not to fit it to a lens wider than 35 mm.

    Strength
    1 to 9 stops, in the title and the first and fourth bullets, named for long exposures and motion blur in changing light. Nine stops turns a 1/250 second exposure into two seconds — the difference between frozen water and a smooth sheet
    Notations given
    BOTH, in the title: ND2-400 and 1-9 f-stops. The two notations describe the same thing from opposite ends — ND2 passes half the light and ND400 a four-hundredth — and publishing both saves the arithmetic. The hub above asks for exactly this, and the 186 € NiSi here gives ND0.3-1.5 instead, a third notation again
    Fixed or variable construction
    VARIABLE, and both filters on this shelf are. A variable ND is two polarising layers rotated against each other, which is why it costs less than nine separate filters and why it has the failure the hub above warns about at the extremes
    Thread size
    67 mm, in the title
    Stated colour cast
    NOT ADDRESSED. The second bullet claims intense colours and high contrast from Japanese AGC glass; neutrality is never claimed and no cast is denied. On a variable ND that is the specification most worth having — the 186 € NiSi here sells its True Color coating precisely on preventing a yellow tint
    Coatings
    Not counted. Japanese AGC glass is named in the second bullet and no layer count appears, where the same maker publishes eighteen layers on its UV and polarising filters
    Frame thickness
    7.4 mm, in the third bullet, described as very slim with a CNC trapezoid pattern that raises friction so it can be fitted or removed anywhere. Seven point four millimetres is thicker than any polariser on this shelf, which is inherent: a variable ND holds two rotating elements
    Amazon reference
    B09BCJ6N8G (same reference on 6 Amazon marketplaces)
    EAN
    6936069271669
    • Two notations published — ND2-400 and 1-9 stops — so no conversion is needed
    • A published 7.4 mm frame with a CNC pattern for grip
    • No colour cast claim either way, on a variable ND

    Best for: A 67 mm standard or telephoto lens used for long exposures in changing light, where nine stops in one filter beats carrying four.

    ≈ 29 €
    Check price on Amazon
  2. NiSi True Color variable ND filter with its knurled ring and click-stop markings

    NiSi True Color VND, 82 mm, 1 to 5 stops, no X

    One to five stops in five clicks with no X effect, a coating sold on neutrality and vignetting-free use at 16 mm — the variable ND that trades range for quality, at 186 €.

    Strength
    1 to 5 stops, in the title — deliberately HALF the range of the 29 € K&F here, and the restriction is the point. A variable ND misbehaves at its extremes; stopping at five keeps the filter inside the range where two polarisers still darken evenly
    Notations given
    A THIRD system: ND0.3 to ND1.5 in optical DENSITY, alongside stops in the title. Density is logarithmic — 0.3 is one stop, 1.5 is five — and it is the notation used on cinema filters. Between this page, the K&F’s ND2-400 and the stop figures, this shelf carries three ways of saying the same thing, which is why the hub above asks which notation is given
    Fixed or variable construction
    VARIABLE with FIVE DEFINED CLICK-STOPS, in the second bullet — and clicks are what a variable ND usually lacks. A continuous ring cannot be returned to the same setting twice; five detents mean the third stop is the third stop on every shot of a sequence
    Thread size
    82 mm, in the title — the largest thread in this catalogue, and the size the buying advice above says to buy for and step down from
    Stated colour cast
    ADDRESSED DIRECTLY, alone on this shelf: the first bullet says the exclusive True Color coating prevents the yellow cast common to other brands and guarantees absolutely neutral reproduction with no colour falsification. On a variable ND the yellowing at strong settings is the defect people complain about, and this is the page that names it
    Coatings
    UP TO TWENTY anti-reflective layers, in the third bullet, with double-sided water- and oil-resistant coatings. Fewer than the thirty the NEEWER polariser on this site publishes; more than the unnumbered coating of the 29 € K&F here
    Frame thickness
    NOT PUBLISHED as a figure. What the fourth bullet gives instead is the engineering: a LARGER FRONT THREAD to avoid vignetting at 16 mm, and a matt black interior to absorb stray light. Sixteen millimetres is a specific, checkable claim, where the K&F here says not below 35
    Amazon reference
    B09K57XSZS (same reference on 6 Amazon marketplaces)
    EAN
    6972949372941
    • No X effect, stated explicitly — the failure a variable ND is known for
    • Five defined click-stops, so a setting can be returned to exactly
    • One to five stops, half the range of the 29 € K&F

    Best for: Video and wide-angle landscape work where the filter has to stay neutral, return to a known setting, and work at 16 mm.

    ≈ $245 / £178 / 186 €
    Check price on Amazon

Each amount in a write-up is what the listing showed when that page was written. The figure next to the product is pulled in as you read, and it is the one that counts.