A layman’s guide to ND filters

How to set up and use a variable ND filter: step 2

What is an ND filter used for – and how should you use it? If you’re new to photography you might understandably have a few questions about some of the equipment.

There are a number of things you need to consider when buying an ND filter and using it for the first time.

In our latest layman’s guide to fundamental gear we answer some of the most common questions photographers have.

How to set up and use a variable ND filter: step 2

What are ND filters?

Conventionally, these are neutral grey filters that effectively reduce the amount of light entering the lens. Unlike graduated neutral-density filters, the light-stopping effect is theoretically equal across the entire image frame.

How do ND filters work?

The most common type of ND filter is made from resin or glass, and is available in a variety of strengths. Typically, these equate to anything from a single f/stop to 10 f/stops; denser filters enable increasingly longer exposures.

Variable ND filters are also available, which are based on a pair of polarised elements. When rotated, the effective strength can be increased or decreased as required.

SEE MORE: Using filters – the only cheat sheet you’ll ever need to get beautifully balanced exposures

Who makes ND filters?

There’s a wide range of manufacturers to choose from, including B+W, Cokin, Formatt, Hoya, Kenko, Lee, Polaroid, SRB Griturn and Tiffen.

Regular screw-in ND filters cost between about £20 and £150, depending on size and quality. Variable or so-called ‘fader’ ND filters start at about £30, but you can expect to pay around £150 for a good one.

When should I use ND filters?

They’re useful for enabling wide apertures under sunny lighting conditions, when you want to reduce the depth of field.

Higher-density filters are great for enabling long exposures under bright lighting, therefore creating motion blur in weirs and waterfalls, or for clearing busy street scenes of people walking about.

SEE MORE: What is the best filter to have in your camera bag?

How do I attach ND filters to my SLR?

They’re available either as circular, screw-in filters that attach directly to 
the lens’s attachment thread, or as square or rectangular filters that mount in a filter holder.


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