Neutral density filters are one tool you can use to control exposure in their ability to reduce the amount of light that enters the lens. However, the extra depth does make this filter prone to the effects of flare.Taking control of exposure for creative effects is one the pure joys of photography. It’s possible to extend exposure times by up to around eight stops and get usable images, and color rendition, tone and contrast are all pretty good. In use the Kenko filter provides a stop of exposure extension at the minimum setting, and a blue X across the image at the maximum marked setting. However, the overall build quality is good. This is a nice design feature, particularly for video, but the rotation itself isn’t quite as smooth as with some of the other filters on test. The Kenko is a relatively deep filter, but it has the very useful addition of an optional knob that can be screwed in to assist with the easy rotation of the front element. The depth makes the filter prone to flare It’s also a pity you can’t get the Vario in an 82mm diameter.
They certainly don’t include moisture or fingerprint resistance, as the filter attracts both. Hama claims the filter is coated, but gives little detail of the benefits. We found that increasing the intensity to the maximum marked setting produces a heavy black X, but pull back a little and you can extend exposure times by almost eight stops (although images do need retouching to remove the color cast).Ī setting of around five stops gives the cleanest results. Hama’s slimline variable ND filter is well made for the price, with a smooth rotation between the two elements and just enough friction to hold its position when set.Ī slight textured edge to the front element makes adjustment easy, and there are clear markings between the minimum and maximum points.Īt the minimum setting the filter enables you to lengthen the exposure by one stop and influences color with a slight coolness. No-frills design, fit and finish not good in wet weather -A better case is required to protect the filter Here we take a look at six variable ND filters and discuss how they perform. It's also worth noting that if a variable ND filter is rotated too far, almost all will reveal a darkened X, which will appear on your photo too. You might also know variable ND filters as 'faders', as many will produce a slight color cast (hence why many photographers prefer traditional neutral density filters). When the user rotates these two filters against each other, the elements restrict the amount of light that's able to pass through. However, a variable neutral density filter is essentially two polarizers fixed together to form one screw-on filter. Traditional ND filters for photographers aren't able to be adjusted, meaning that their opacity – and the amount of stops of light reduced – will remain constant. This is where a variable ND filter comes in handy, giving you the ability to control how much light is coming through – and the flexibility to choose exactly which aperture you want. However, if you're working on a bright and sunny day, there's only so low you can set your ISO.
At ND2 you’ll get a one-stop reduction in light transfer, and at the ND400 position there’ll be an eight-stop reduction.Ģ: At maximum density you’ll see a cross effect that often creates an uneven exposure.ģ: Variable NDs can create unwanted effects with ultra-wide lenses, so longer focal lengths are best.Ĥ: Some filters have coatings that help improve light transmission and reduce reflections. These include creating milky seas and skies, erasing moving people from an urban scene and creating dramatic light trails.ġ: A variable ND filter may present its density range as ‘ND2-ND400’.