Circular ND Filters

ND (Neutral Density) filters are unique tools in photography, not only landscape. It is not unusual to see beautiful photos with the presence of silky water, sea without ripples, or streaked clouds and very soft light. Obviously with the advances in post-processing, many will think about the use of retouching software, believing that anything can be “fixed in post”. However, as most professional photographers will tell you, the best results are achieved in camera with ND filters.

So what is an “ND” filter? The abbreviation stands for “Neutral Density”, literally they are colour neutral. Filter manufacturers produce ND filters in glass (of varying degrees of quality dependant on the manufacturer) or resin (a lower quality optical product) and are specifically designed to evenly reduce the transmission of light across the spectrum.

ND filters are an additional method (after ISO, aperture and shutter speed) to manage the light when shooting; a critical tool in the hands of the photographer to be able to get the results he wants.

What ND filters are for?

An ND filter allows you to lengthen the shutter speed. The light reduction of a filter is measured in absorbed “stops“. At each stop the shutter speed must be doubled (assuming f/ value and ISO stay the same)  to obtain a photo with exposure similar to that of the unfiltered scene. For example: without a filter we take a well-exposed photo with half-second shutter speed, but we want to get silky water and accentuate the movement of the clouds. We introduce a 6-stop ND filter and the light is reduced, therefore the shutter speed can be slower, by how much? 64 times.

This is because we must double the shutter speed for each stop of light absorbed. In this case for 6 times, i.e increase by 2 to the power of 6: 2 x 2 x 2 x 2 x 2 x 2 = 64.

The ND filters are also marked with this value, you can see 6-stop ND filters indicated as ND64. A half-second without the filter corresponds to 32 seconds with an ND64 filter. Taking a photo for 32 seconds with the filter will result in silky water and some hints of movement on the clouds, nothing prevents you from using much darker ND filters and trying longer times. NiSi offers filters up to 20 Stops.

Types of Circular ND Filter

We pride ourselves on having a comprehensive range of products to suit all photographers needs: circular screw-in, circular Push-to-fit (Swift) and circular Magnetic (JetMag Pro), in different sizes and densities. We offer products of the highest quality to interfere with the quality of your lenses, take a look at some of the options.

Circular screw-in filters

These are the most common ND filters, they are screwed directly on the lens front thread, and being as large as the diameter of the lens, they cost less (less glass = less cost). They are perfect for getting started but fail to have the same versatility as Swift or JetMag Pro filters.

Magnetic JetMag Pro System

The JetMag Pro Filter System is designed for photographers who demand speed, stability, and versatility in their gear. With an innovative magnetic design, ultra-slim frames for wide-angle lenses, and a unique locking mechanism, JetMag Pro ensures that your filters are installed and secured quickly and effortlessly. Ideal for landscapes, nightscapes, filmmaking, and more, this system adapts to various lenses while reducing glare with a specialised nano-coating.

The NiSi JetMag Pro FS ND filters are available in the following densities and sizes.

All filters can be used individually only with the magnetic adapter ring of the same native size as the filter.

Push-to-fit Swift System

Discover the convenience of the NiSi Swift Full Spectrum ND Kit, essential for both professional and amateur photographers and videographers. This kit comprises three Full Spectrum Neutral Density (ND) filters: ND8 (3 Stop), ND64 (6 Stop), and ND1000 (10 Stop), accompanied by various adapter rings to fit all thread sizes in the following kits:

All filters can be used individually only with the Swift Adapter Ring of the same native size as the filter.