What Does A Nd Filter Do

What is an ND filter and when would y'all use one?

(Image credit: Digital Camera Globe)

An ND filter is used to control the amount of lite that reaches the sensor without having any effect on colours, tone, or contrast within the scene. Effectively you cake out light like a tinted window on a car does. The letters ND stand for neutral density and an ND filter can be a fixed strength or its strength can be variable.

The question is, why do you desire to hold dorsum light when lots of low-cal is often a benefit? At that place are a several creative reasons to use an ND filter. Yous may want to achieve a long exposure to capture creative movement, such every bit blurry water, clouds, swaying vegetation, or even crowds walking. You might also demand to hold back light and so you can use a wide aperture for a shallow depth-of-field in a portrait epitome.

ND filters are also useful when shooting video because of the importance of maintaining the same shutter speed.

ND filters are non the same equally ND grads. ND grads take a variable forcefulness from bottom to top to tone down vivid skies, whereas ND filters take a fixed, all-over effect and are used for overall exposure control.

Regular vs variable NDs

Long exposure — Photographers use ND filters to allow long exposures fifty-fifty in bright daylight. This gives waterfalls and rivers a smooth, silky blur. (Paradigm credit: Digital Camera Earth)

ND Filters come up in dissimilar sizes, shapes, and strengths. Circular screw-in ND filters attach to your lens' thread but you demand to get one that fits the filter size for your lens and it's possible, if you have several dissimilar lenses, the filter size will be unlike for each one.

Variable ND filters are circular and you lot merely rotate them to modify the strength of the low-cal blocking issue.

Square or rectangle-shaped NDs are pop in photography but to use them you also have to have a filter holder that attaches to the lens via its screw-thread. The positive side of this is ane filter holder will allow you to fix any same sized filter on the forepart of the lens, so if y'all accept a choice of different forcefulness filters it's easy to swap them around as the lite changes.

Though arguably, it'south not every bit convenient as a variable filter for quick changes which is why variable NDs are the choice for film-makers.

Variable ND forcefulness

H&Y Revoring VND+CPL — Videographers use quickly adjustable variable ND filters to maintain the same aperture and shutter speed settings in changing light. (Image credit: Rod Lawton/Digital Camera World)

The filter strength you need naturally depends on the atmospheric condition you lot are shooting in and the event you want to achieve by slowing shutter speed down. Typical strengths can vary from simply 1-stop of light to 15 stops, with other grades in-betwixt. Of course, the big the number, the more light it blocks out. A typical variable ND filter will provides a variance of 1 to eight stops of low-cal.

Photographers utilize fixed-strength ND filters to allow long exposures to blur water and clouds. Videographers use lower-strength variable NDs of 1-four stops to keep the lens aperture (iris) value and shutter speed (shutter bending) the same in irresolute lighting weather to give the video a consistent 'look' throughout.

Read more:

• Best filter holders (opens in new tab)
• Best ND filters (opens in new tab)
• Best variable ND filters (opens in new tab)

Jon started out as a film-maker, working as a cameraman and video editor before becoming a writer/director. He made corporate & circulate programmes in the U.k. and Heart Due east, and also equanimous music, writing for Telly, radio and cinema. Jon worked as a lensman and announcer aslope this, and took his video skills into magazine publishing, where he edited the Digital Photo magazine for over fifteen years. He is an expert in photo editing, video making and photographic camera techniques.