ND Filters: A guide

ND Filters: Your Friend in Tough Lighting 

The ND filters, also known as the Neutral density filters are a very popular accessory used by many professional photographers today. It is actually one of the tools that should be in every photographers go to equipment. But for some reason the ND filter seems to sound to most as a very professional or unneeded accessory. In this article we will break down the basics of ND filters, what they do and just how useful they can be in your photography arsenal. 

Filters in Photography

Filters are usually clear pieces of glass that are designed to have some effect on the light going inside your cameras sensor. These filters are attached to the front of the lens and therefore they alter the light passing in to the lens 

ND Filters

A ND filter (short for Neutral density Filter) is a type of filter that when placed on the lens helps to reduce the amount of light passing that makes its way to the camera sensor. They have virtually the same function for your camera as sunglasses do for you eyes. Only difference is they don’t change the color of the light passing in the sensor hence the word ‘neutral’. You might be wondering, whats the point of reducing the light going in to the sensor. The answer is you can add a range of effects to your photography you wouldn’t have been able to before. Some of these we will highlight. 

Aperture

Generally the rule of photography is the more light around you the better. But that doesn’t apply in all cases. If you have ever experimented with wider apertures in broad daylight you know what you can never take a photo on a f/1.8 aperture without overexposing the picture and ruining it. ND filters allow you to make use of wider apertures without overexposing the picture. So now you get a shallow depth of field and selective focusing effect that under normal lighting conditions would go beyond the shutter speed abilities of the camera. 

Shutter speed

Another effect of the ND filter is that it can give you motion blur caused from a slower shutter speed. With less light going in to the camera sensor you would need to crank up the shutter to be a little more compensating. What this will do is blur anything that is moving in the frame. While this is generally not desirable it would produce a fantastic effect when you what to emphasize movement. If you have ever seen a picture of busy roads with the head lights and tail lights of cars making lines thats a result of using an ND filter with a slower shutter

Numbers on ND filters 

ND filters usually come in varying intensities of darkness based on what sort of condition you will be using them in. However they do make the job easy because most ND filters come with labels telling you how many stops of light they will darken in your exposure. Generally for every stop of an ND filter you halve the amount of light coming in.