There are a number of filters on the market today. You’ve probably heard of polarizers, warming filters, and cooling filters, but what about neutral density filters? The language sounds overly complicated, but rest assured it’s not. If you’ve ever wondered what one these filters does, and how you might use it in your own photography, you are about to find out.
Turning the volume down on light
Sometimes there’s so much light outside that it limits your creative options as a photographer. In the middle of the day, the sun gets very bright. If you don’t use a fast shutter speed, your image will end up overexposed. Most of us use fast shutter speeds in the middle of the day anyway (your camera will select it for you if you’re shooting in automatic mode), but that’s not always the best choice. Certain photographic effects, like motion blurs, require you to use slower shutter speeds.
A neutral density filter turns down the volume on the light. With less light coming through the lens, you won’t need to use as fast of a shutter speed to get a correct exposure. The same goes with aperture and ISO speed. With a neutral density filter you will have a little more freedom to use wider apertures or larger ISO speeds during the middle of the day, something that’s useful for a number of photographic effects.
What are some uses of neutral density filters?
Most photographers use neutral density filters when they want to slow down waterfalls or blur out backgrounds. In order to make water look silky smooth, you have to use a fairly slow shutter speed. If it were early in the morning, a time when light tends to be faint, there would be no problem using your lens without a filter. But when the light is much more direct and intense, you run the risk of overexposing your photo.
The same goes with taking portrait pictures. There are times when you will want to draw more attention to your subject by blurring out the background. To do that, you need to use a wide aperture. If your camera doesn’t allow you to use a super fast shutter speed (like 1/000s) to block out some of that extra light, you will end up with an image that is too bright. The neutral density filter blocks out light from all wavelengths, giving you a darker picture overall.
What types of neutral density filters are available on the market?
There are plenty of neutral density filters on the market today. It really depends on how much light you need to keep out of the photo you’re taking. All neutral density filters are given a rating that corresponds to an “f-stop” reduction. That’s a fancy way of saying each neutral density filter you attach mimics an increase of your shutter speed by a certain number of twists. If you get an ND2, it’s like increasing the shutter speed by one stop. Get an ND4, and the light coming into the camera would be like the light you would get from increasing the shutter speed by two full stops. (Note: you aren’t actually increasing your shutter speed. You’re just getting less light from outside, something that mimics a faster shutter speed in one way).
At the very end of the scale, you have the ND8192. This powerful light blocking filter reduces the light by a full 13 stops. I personally can’t think of how I would use something like this, but you might want to use it to get a very intense motion blur effect (similar to the ones you see in nighttime photography) during the day.
What is a graduated neutral density filter?
Some neutral density filters aren’t so “neutral” after all. A graduated neutral density filter blocks more light on side than the other. Half of the filter might block out 4 f-stops on one side and only one f-stop on another. Where might be this be useful? Landscape photography is an immediate candidate. When you are taking pictures of landscapes, the sky tends to be much brighter than the ground underneath it. By using a graduated neutral density filter, you can get the right brightness levels in the sky and the ground at the same time.
Do I need a neutral density filter?
Unless you intend to create to create motion blur effects during the middle of the day, you probably don’t need a standard neutral density filter. It’s easy enough to turn down the intensity of the light by simply using your camera settings. When you switch to a faster shutter speed, a smaller aperture, or a lower ISO speed number, you are effectively blocking out more of the sun’s light. The standard neutral density filter helps only when you can’t do one of these 3 because you are going after a certain photographic effect.
Graduated neutral density filters, on the other hand, are a must have for anyone. They are great because they let you have your cake and eat it too. You get rich and colorful skies without making the ground look too dark. I would highly recommend them to anyone who is interested in getting better at landscape photography.
Photo At The Top By Kain Kalju