Bright light isn't always a good thing. Get some serious stopping power as we test six of the top options to find the best ND filter for photographers…
Fast shutter speeds are great for freezing motion, but that's not always what you want when you're taking a photograph.
Mount your camera on a tripod and set a long exposure, and you can add motion blur to subjects like weirs and waterfalls, for a much more dreamy look.
Tripods also make it possible to blur people and vehicles out of busy street scenes as they're walking around, for cleaner architectural shots.
The only problem is enabling a long exposure in bright light, such as on a very sunny day, as over-exposed and even blown-out photos are likely.
One solution is to fit a high-density neutral filter to your lens, typically one with a rating of 10 stops.
These dark filters reduce the amount of light passing through the lens. If, for example, a sunny scene would require a setting of f/11 at 1/125 sec for a correct exposure, fitting a 10-stop ND filter will enable you to slow the shutter speed to eight full seconds at f/11.
Another option, which is also particularly advantageous when shooting video, is to use a variable or 'fader' ND filter.
Based on two polarising filters, one of which is rotated against the other, these usually give a range of between two and eight stops.
Best ND filter: 01 Tiffen IR ND 3.0
Price: £65, $90 for 77mm fitting
Tiffen's older standard ND 3.0 filter is a typical triple-density filter that gives the usual 10-stop light reduction.
However, in our tests it gave a very pronounced red colour cast when used on a Nikon D7000, and the effect was still noticeable to a lesser extent when fitted on a D610.
According to Tiffen, the new IR Cut edition is specially engineered to reduce 'infra-red and far-red pollution'.
In our tests, we did find that it gave a much more neutral colour balance on both cameras.
The standard of construction is very good, with a low-profile design to combat vignetting, even when used on ultra-wide lenses, and no light seepage around the edge of the filter.
The claimed 10-stop density is very accurate. If you're on a limited budget, this filter is a very good buy.
Pros… Very good colour accuracy, low-profile design.
Cons… Metering with the filter fitted tends to give dark images.
We say… Very good performance and excellent value.
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Best ND filter: 02 Light Craft Workshop Fader ND Mk II
Price: £100, $130 for 77mm fitting
The original version of this variable ND filter proved highly popular, and the new Mk II edition has been enhanced to avoid any softening of images at long focal lengths, while also reducing vignetting with wide-angle lenses.
However, as with other filters of this type, the amount by which you can increase the effective density is diminished significantly when you're using wide-angle lenses.
Premier Ink, the UK distributor, is very upfront about this, stating that while a reduction of up to nine stops is available at a 100mm focal length, this shrinks to as little as three stops at 12mm, before a dark cross begins to appear across the image.
These figures are for actual (rather than effective) focal lengths when using an APS-C format camera, and were borne out in our tests.
Pros… Good image quality with minimal colour shift.
Cons… Limited stopping power with wide-angle lenses.
we say… It's very good value for a variable ND filter.
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Best ND filter: 03 B+W MRC 3.0/1000x ND
Price: £105, $150 for 77mm fitting
B+W offers two editions of its 10-stop ND filter. Both have a reassuring weight, despite their thin profile, owing to the inclusion of high-quality glass plus brass mounts.
The MRC version, which we're reviewing here, features dirt-, water- and scratch-resistant multi-coatings instead of a single coating, and is about 30 per cent dearer to buy.
Fitting the filter to our Nikon lenses with 77mm attachment threads proved a little tricky and fiddly at first but got easier over time.
One thing that remained constant, however, is that the B+W gave a noticeable red tint to images captured on both the D7000 and D610 cameras we used for testing.
Colour accuracy was actually much better from the Tiffen filter, which costs far less money to buy.
Pros… Solid build yet with a very low-profile design.
Cons… Noticeable red colour cast on both test cameras.
we say… It's pricy, so colour inaccuracy is disappointing.
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Best ND filter: 04 Formatt-Hitech Multistop ND
Price: £130, $145 for 77mm fitting
The advertised stopping power of this variable density filter is less than that of the Light Craft Workshop filter, at two to six stops.
In our tests, however, both gave practically identical maximum reductions at varying focal lengths.
The Formatt-Hitech's construction boasts 'highest quality broadcast glass' built into to an aluminium housing.
The overall build is quite chunky, based on a pair of rings, one fixed and one rotating.
However, the front ring is considerably larger in diameter than the rear one, which helps to avoid vignetting when attached to wide-angle lenses.
The colour accuracy and overall image quality produced are practically identical to those of the less expensive Light Craft filter, but the Formatt-Hitech feels a little more robust.
Pros… Robust build and high-quality components.
Cons… Loses effectiveness with wide-angle lenses.
we say… Good value considering its upmarket build quality.
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Best ND filter: 05 Lee Big Stopper 100mm
Price: £100, $140 without holder
Unless you already use Lee 100mm filters, when you buy this you'll also need to purchase a Foundation Kit and adaptor ring, which can add up to £100 ($120) to the price of this square filter.
All components are engineered to a very high standard, though, making it an attractive system - this particular filter is a real favourite with pro photographers.
The Big Stopper filter itself has to be used in the rear tray of the filter holder, and has foam padding around its rear edge.
This is to stop any stray light from entering through the top, bottom or sides of the assembly.
In our tests, the light reduction proved true to Lee's claims of 10 stops but our sample images, taken using both the D7000 and D610 cameras, had a noticeable green colour cast.
Pros… Image and build quality are both very good overall.
Cons… We experienced green colour casts.
we say… Expensive if you also need to buy the mounting kit.
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Best ND filter: 06 Hoya Pro ND 1000
Price: £165, $120 for 77mm fitting
Something of a household name, Hoya filters have long been popular with photographers all around the world.
A wide range of Pro ND filters are available in increments from two- to 10-stop options, each of which uses the same 'Metallic ACCU-ND' type of coating.
Hoya claims that this not only yields a truly neutral colour balance without any noticeable colour casts, but also maintains colour integrity between different strengths of filter.
In our tests, we found that the Hoya 10-stop filter gave the most accurate colour rendition of any filter in the group on both our cameras.
Its profile isn't quite as slim as those of some of the competing filters but we still didn't experience any vignetting, even when using the Hoya on ultra-wide lenses.
Pros… Accurate colour balance, good metering with filter fitted.
Cons… More expensive than any other filter in the group.
we say… It's an expensive option but delivers standout results.
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