If you’re looking for the best filter for your camera, then the variable ND could be a great choice. Here we review the NiSi True Colour ND-Vario 1-5 stop circular filter.

NiSi True Color ND-Vario 1-5 stops – at a glance:

  • £89-£189
  • Available in 40.5mm to 95mm sizes
  • Blocks 1 to 5 stops of light
  • True Color polarising film
  • Cap and case included
  • www.nisioptics.co.uk

Neutral density filters are handy tools for photographers. By reducing the amount of light entering the lens, they allow the use of large apertures on bright days, or long exposure times to introduce motion blur, for example when shooting water. They’re also invaluable for videographers, enabling sufficiently slow shutter speeds to give a smooth rendition of moving subjects.

Compared to fixed-density alternatives, variable NDs promise to be particularly useful. By rotating the front section of the filter, they allow you to change their strength and achieve a target shutter speed without having to buy and carry multiple filters. However, it’s not necessarily that simple.

NiSi True Color ND-Vario 1-5 stops

NiSi True Color ND-Vario 1-5 stops, 77mm size

Variable ND filters work by using two polarisers, one in front of the other. When they’re perfectly aligned, the density is at its minimum; rotate the front one and it successively increases. But this can come with unwanted colour shifts and uneven darkening across the frame at high densities (so-called cross effects).

With its latest True Color ND-Vario filter, NiSi has aimed to minimise such problems. The firm says it has employed a polarising film that introduces no colour cast and effectively eliminates cross effects, even at the maximum 5-stop density. The filters are made from HUC (High Ultra Clarity) optical glass, with a smart two-tone frame design and an unusually pronounced grip around the edge.

NiSi True Color ND-Vario 1-5 stops: Key features

  • Box contents: The package includes a push-on cap, sturdy plastic case and tough fabric outer pouch
  • Coating: There’s an oil- and water-repellent coating on the front, and nano coating to suppress flare
  • Density scale: Unlike cheap variable NDs, the filter is marked at 1-stop intervals, with hard stops at the extremes of the usable range
  • Screw-in pin: This removable pin allows single-finger control over density, but unfortunately, blocks the lens cap from fitting
NiSi True Color ND-Vario 1-5 stops kit contents

The filter comes with a protective case, fabric pouch, push-fit cap and screw-in adjustment pin

I tested the 77mm filter, which costs £149, using the 60MP Sony Alpha 7R IV with 16-35mm f/4 and 24-105mm f/4 lenses. In short, it delivers impressively on its promises. It brings no degradation of sharpness or detail, and no measurable colour cast when tested against a colour-checker chart.

If I’m being picky, I detected a slight unevenness in density beyond 4 stops, but it’s only visible if you point the camera at an evenly illuminated surface, and shouldn’t be problematic in real-world use. Water simply rolls off the glass leaving no trace, while fingerprints wipe away easily using a microfibre cloth. The density scale is perfectly accurate.

NiSi True Color ND-Vario 1-5 stops desnity scale

A density scale is marked around the rim of the filter, and is perfectly accurate

One thing you do need to keep in mind, though, is the polarisation effect. This is controlled by the angle of the front section, so adjusting the density can also affect such things as reflections. In some situations, you may need to partially unscrew the filter to get the best combination of density and polarisation.

NiSi True Color ND-Vario 1-5 stops: Sizes and pricing

NiSi True Color ND-Vario filters are available in sizes from 40.5mm to 95mm, for £89 to £189. Looking at some of the most popular diameters, 67mm costs £129; 72mm is £139; 77mm is £149; and 82mm £169. This counts as good value compared to other high-end brands. Cheaper options exist but generally lack the same quality and feature set.

NiSi True Color ND-Vario 1-5 stops: Our Verdict

NiSi’s True-Color variable ND works very well, doing exactly what it promises with no fuss. It’s optically excellent, comes in a comprehensive package, and represents good value for money, especially given the sheer quality on offer.

Amateur Photographer Testbench Gold - 5 stars