A neutral density filter, also known as ND filter, is a piece of equipment that most professional photographers will not go anywhere without. Novice photographers that don’t know better, are less interested in using ND filters because the product looks dull and austere, it does not give special effects and is not colorful. After all, you can adjust the amount of light through your camera, right? What’s the point of using an add-on filter to filter light through your lens? There is more to these filters than meets the eye. There is probably a good reason that most pros and advanced amateurs cannot go without one.
First, let’s take a look at some of the different kinds of ND filters. Neutral density filters come in a variety of sizes for the wide variety of lenses that are available. The filters also are available in different strengths or exposure factors as well, such as:
One stop (2x)
Two Stops (4x)
Three stops (8x)
Six stops (64x) and
Ten stops (1024x)
Using a neutral density filter is pretty easy and simple. All you have to do is to screw it on to the lens and when you aim at your subject, your camera will take care of the exposure levels. Your camera accomplishes this by either reducing the shutter speed or adjusting the aperture. For example, if the normal speed of the shutter is 1/125 sec, your camera will adjust it to 1/15, once the 8x filter is mounted. And if the normal aperture is f/22, it will be opened up to f/8 when you put on the filter. You might be saying to yourself, “What’s the big deal because my camera can do the same thing right out of the box?”
Well, the ND filter can reduce the amount of light that enters through the lens without altering the color balance. If you are shooting outdoors under the bright summer sun, the balance between the landscape, the subject and the sky can be achieved with a ND filter. Your ND filter also offers a touch of manual versatility if you have a fully automatic camera. If you are shooting in a low light condition, it will be impossible to take shots when you move out into the sun because your camera will shoot with a flash in blistering shutter speeds even if your opening is in the narrowest setting. Using an ND filter will minimize the light and thus allow you to take great shots.
Architecture photographers find ND filters very useful. When they take photographs of buildings, they often set the exposure slow. However, a 1/2 sec exposure level guarantees a blurred image of a passerby. By using an ND filter, you can set an even slower exposure level down to four seconds. Amazingly, the streak of the passerby disappears in this setting. It is a simple yet very effective technique to eliminate passersby and the distractions that their movements create.
Another benefit of ND filters is that you can take ethereal shots of flowing rivers and waterfalls. If you have seen a photograph of a waterfall or a river with a silky smooth cottony flow, there is a good chance that a neutral density filter was used to reduce the shutter speed and take the shot. The slow shutter speed is responsible for the blurring effect. If you are in front of a waterfall under a bright sun, your automatic camera will probably set the shutter speed to 1/125 sec. By using a ND filter, your camera will automatically set the speed to 1/15 sec, allowing you to get the desired effect.
The advantages of neutral density filters are not only limited to adjusted shutter speeds. You can improve your aperture, too. In flower photography, photographers often have a problem with the background spoiling the subject. This has something to do with the depth-of-field – if your camera has a great range, your background can achieve sharpness that distracts the subject. By using your ND filter, it reduces the depth-of-field, blurring your background and giving the full opening to the subject. This will result in stunning close-ups.
Certainly, there are many more things that can be done with a neutral density filter; it’s just a matter of imagination and a touch of creativity. Apart from the skills that come with experience, a ND filter can be the thing that separates the shots of an amateur from the shots of a professional. Simply put, these filters help make photography an art form.