Filters & The Landscape

Filters are a big part of landscape photography, and every photographer needs a few. Though you'll hear some shooters talk about all the possibilities available through the digital darkroom, achieving an effect in-camera is often easier and simplifies your Photoshop workflow. Some effects, such as the polarizer's reduction of glare on water, aren't even possible in a computer.

Polarizers
If you have only one filter, it should be the polarizer—the most useful of all filters. Though most people think of a polarizer for darkening skies or eliminating reflection, it does much more to improve contrast in a photograph.

Polarizers eliminate that annoying sheen and glare from vegetation, allowing the true colors to show. For this reason, I use polarizers in forests on overcast or rainy days. Polarizers can also cut out reflection from moisture in the atmosphere, reducing haze and therefore darkening the sky. If I need to reduce the exposure in the sky, I'll look to a polarizer first.

Polarizers reduce the light reaching the film or sensor by one to two stops, meaning an exposure adjustment is needed. Your camera's auto-exposure system will handle it, but be aware that the exposure will change. This change in exposure is sometimes an advantage if you need a longer shutter speed to blur water in a stream. In fact, I've stacked a polarize with a neutral-density (ND) filter to simply get longer shutter speeds. Be careful stacking filters, however, especially with wide-angle lenses, as you risk vignetting in the corners. Make sure to remove any other filter, such as a UV filter, as well.

A polarizer is most effective when the lens is 90 degrees to the sun. The impact of the filter is lessened or completely lost otherwise. I suggest that you not leave the filter attached to your lens. It's not worth the loss in light unless you're gaining the benefits of the polarizer.

The easy way to tell if a polarizer is going to have any effect is to hold it in front of you and rotate it. Make sure that you're facing the same direction as the camera and that the filter threads are facing you. If you like what you see, use the filter in that position on the camera.

Graduated ND Filters
Graduated ND filters work like half of an ND filter—half of the filter is clear and the other is dark. Such filters can be used to control contrast in a landscape situation where the range of light is beyond the tonal capabilities of the film or sensor. They're typically used with a bright sky over a darker landscape. This high contrast makes it difficult to capture shadow and highlight details with a single exposure.

The grad filter balances the dark and bright areas, and brings them within the dynamic range of the film or sensor, enabling you to capture the full range of light in one shot.

Grad ND filters are available in different densities, normally up to four stops. They come with two different types of transitions: a gradual soft transition or an abrupt hard transition. Many landscape photographers prefer the soft-transition filter as it blends the area of change between the dark and clear portion of the filter for a more natural look.

Screw-mount filters force you to position the transition in the middle of the frame, which isn't always ideal for a landscape photograph. Instead, many photographers prefer rectangular filters that are held in front of the lens or slipped into a filter holder.

The Cokin "P" holders and adapters are widely available and inexpensive. I generally handhold my filters in front of the lens. This allows me to work fast in quickly changing light. Plus, I find it more convenient than attaching adapters and holders. This is easiest to do when shooting with a tripod.

Many wide-angle lenses have a filter diameter as large as 77mm, however, so it's important to use a large enough filter to cover the entire front element. Several manufacturers, including Singh-Ray, Lee and Tiffen, make filters that measure 4x6 inches, available with the usual densities and transitions. These oversized filters are easier to handhold. Plus, being so large, they give the photographer more creative options such as deliberately moving the filter up and down during an exposure to further' feather" the transition area.

To determine what strength of filter you need, it's best to take a meter reading of the highlight, then the shadows, and note the difference in exposure. Using too strong of a filter can result in the highlights being darkened too much and thereby a loss of detail.

Though some photographers forego the use of grad filters and opt for making two or more exposures of a scene and blending them together in Photoshop, using a grad filter takes a fraction of the time that would be spent achieving similar results on the computer.

Landscape Filters Chart PDF

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ND Filters
Rod Barbee'sND filters reduce the light reaching the film or sensor without altering the color of a scene. They usually come in one-stop increments from one to four or more stops, although they're rarely designated in stop increments. Instead, you'llsee a filter marked as ND 0.3, which means the filter reducesthe light by one stop. The table above will help you translate these designations.

You may also see filters marked as NDx4. This ND filter reduces light by two stops because it only allows one-quarter of thelight through; an NDx8 only allows one-eighth of the light through, resulting in a reduction of three stops.

With moderate ISO film and digital cameras with minimum ISO settings of 200, it can be difficult to achieve slow shutter speeds in bright light. This is a problem if you want to render the flow of a river with a slow shutter speed; but even a small aperture doesn't allow for a slow enough shutter speed.

ND filters become valuable anytime you want to blur the motion of water, clouds or flowers blowing in the wind. I find ND filters especially useful when photographing on the coast. With longer shutter speeds, you can blur the water over several seconds, creating an ethereal, mist-like effect. The reduction of light also dims the image within the viewfinder, so it's best to establish your composition before adding the filter.

The polarizer, graduated ND and ND filters can make a remarkable difference to your landscape images. Though Photoshop has become a great photographic tool, these filters offer you the abilityto capture scenes exactly the way you want within seconds. I enjoy working with Photoshop, but I use these filters regularly because I much prefer knowing that I got it right at the moment of capture.

To learn about Rod Barbee's upcoming workshops or to order his latest book, 88 Secrets to Wildlife Photography, visit www.barbeephoto.com.

LandscapeFilters Chart PDF

You may need to install the most recent version of Adobe® Acrobat® Reader to view the PDF file.