Exposure Tips for Winter Photography

When winter arrives, many photographers put their cameras away waiting for the warm weather of spring to return before they venture outside to photograph nature. Winter offers wonderful and unique photo opportunities-providing you take a few precautions when photographing in cold weather, and most importantly, understand how to take a properly exposed photograph given problematic metering issues created when photographing snow scenes. To take a correctly exposed photograph in snow, you must understand your camera’s meter and how to compensate for snow’s bright tones and its reflective nature.

UNDERSTANDING YOUR CAMERA'S LIGHT METER

Virtually all camera used by nature photographers today have a built-in through-the-lens (TTL) reflective light meter. The camera light meter measures the light reflected by the subject back to the camera. These TTL reflective light meters are very sophisticated, offering a choice of spot, center-weighted, or matrix, or evaluative metering. These meters are extremely convenient for nature and wildlife photographers since the TTL metered exposure automatically compensates for the effects of lens extension and filters.

In the spot metering mode, almost 100% of the camera meter’s sensitivity is concentrated in a very small area of the viewing screen, typically 4-6 mm in diameter, about the size of a pencil eraser. Spot meters are capable of accurately measuring the light reflected by the primary subject without being influenced by surrounding areas of light and dark. This is particularly useful when metering subjects whose tonality significantly differs from a medium-tone subject.

A center-weighted meter measures the light reflected by the entire scene as seen through the camera’s viewfinder, but its sensitivity is concentrated in the center. The size of this area in the center of the viewfinder varies among different camera models. For example, although the Nikon F3 and F4 both have a 12 mm diameter circle in the center of the viewfinder, the F3 bases its exposure in the center-weighted meter mode on 80% of the reflected light inside this circle, while the F4 is biased at 60%. If your camera has a center-weighted meter, refer to the camera instruction book to determine the meter pattern.

The third type of meter may be called matrix or evaluative, depending on the camera manufacturer. This meter uses a very complicated, state-of-the-art, metering pattern along with a data base of scene information used to determine the proper exposure for a particular scene. The matrix or evaluative metering systems will yield an accurate exposure for most typical scenes encountered in nature.

SUBJECT TONES

Understanding how your camera’s meter works is only part of the equation to a properly exposed photograph. You must also know how to assign tonality to a subject and how to expose for that tonality. Even though a large number of subjects in nature are medium tone, there are some, such as snow or bison, which are significantly lighter or darker than medium tone. In the spot or center-weighted metering modes, the camera will expose the subject being metered, regardless of its tonality, as if it were middle tone. Even though the artificial intelligence and metering pattern of matrix metering systems is very sophisticated, metering a scene with a subject whose tonality is significantly different from medium tone may trick the camera’s matrix meter and result in an incorrect exposure.

I have found that color slide film has approximately a five-stop range of tonality from solid white (with no texture) to solid black (with no texture). The following table gives the range of tonality for color slide film, along with examples of subjects whose tonal values are known and the amount of compensation I use. While many pro photographers may use similar methods, I found John Shaw’s examples (found in his book, “LANDSCAPE PHOTOGRAPHY”) to be a very good starting point for me. Consequently, I have adapted his chart to one that matches my type of shooting.

Consider using the following chart as a baseline. Then create a chart of your own, making any needed modifications that may result from your own tests.

NOTE: Except for situations where I want the subject to appear as a silhouette, I seldom compensate more than -1 stop because, to hold detail in a dark subject, I find that going beyond that amount of compensation is not within a “usable range’ for most subjects in nature. What I mean is that black is black is black. Once I have adequately reduced the light based on spot metering a ‘very dark “subject, any further reduction of light causes the image to underexpose other areas of the photograph (areas in which the meter reading was not taken). Therefore, I prefer to use no more than -1 when spot metering a very dark subject. However, I suggest that photographers make this determination for themselves, based on their own preferences.

Starting from medium tone as a reference, adding more light will make the subject lighter than medium tone. More light can be added by either selecting a larger lens aperture, slower shutter speed, or adjusting the exposure compensation dial on the camera in the plus direction. The reverse applies to take a subject darker than medium tone. Knowing where the tonality of the subject being metered falls relative to middle tone, and how your camera meter works, will allow you to determine the amount of exposure compensation needed to obtain a properly exposed photograph. For example, since the tonal value of snow is very close to extremely white and we want to preserve detail in the snow, add 1 2/3 to 2 stops of light to the camera’s spot meter reading to give snow its proper tonal value in the photograph.

TAKING THE PHOTOGRAPH

Having discussed the concepts of metering and subject tonality, let’s look at three photographs taken in snow and see how they were metered for proper exposure. The two metering systems I used were spot and matrix or evaluative. If the scene I am photographing contains equal amounts of light and dark, experience tells me that the camera’s matrix meter will properly expose the scene. If the scene contains an abundance of elements that are lighter or darker than middle tone, I prefer to use spot metering.

In the High Arctic landscape photograph "Top of The World" of ice, snow, water and sky there was a near equal balance between the light and dark areas. The sun was low in the sky and evenly lit the scene. I knew the camera’s matrix meter reading would produce a properly exposed photograph, so I used no compensation.

The photograph of the coyote titled "Lone Journey" was taken on a sunny day when the sun was not very high in the sky. To get this shot I spot metered the snow and opened up 1 2/3 stop for detail in the snow. We had spotted the coyote from the road just outside Lamar Valley in Yellowstone National Park. Even though he was out of range for my 500 mm lens, I decided to set up my camera, lens, and tripod on the side of the road since it appeared that he was moving toward the road. When he disappeared in some sage, I thought the opportunity to photograph him would not materialize. I was only seconds away from rigging down my setup and returning to our vehicle when he exited from the sage in full view. I had only seconds to take the picture. Since I had set the exposure, shutter speed to freeze motion, and aperture for proper depth of field before the coyote appeared, all I had to do was make sure that the coyote’s face was in sharp focus.

When working in the field, periodically check your exposure. If a photograph quickly unfolds, all you may need to do is focus and shoot. This can save valuable setup time.

The final photograph of a polar bear in the High Arctic jumping across an ice floe titled "Leap of Faith", was another photograph that unfolded very quickly. For more than an hour we watched this bear from the safety of our boat, along the pack ice about 600 miles from the North Pole. I noticed that he was walking toward a break in the ice. I trusted my instincts and thought he would probably jump to the other ice floe. I had previously spot metered the snow and compensated by adding 2 stops of light due to excessive overcast light. My exposure allowed for sufficient shutter speed to freeze his motion if it occurred. All that was left was to follow focus the bear and when he was poised to jump, hold down the shutter button. I was able to record a four-shot sequence as he jumped across the ice floe. Having the proper exposure for the snow scene dialed in ahead of the time insured that I was able to record the action sequence on film.

SUMMARY

Whether you are using spot, center-weighted, or matrix/evaluative metering, it is important to first read the instruction book for your camera, to understand how your camera meters a scene in each metering mode. Experiment with each meter pattern under various lighting conditions and subject tones to understand how the camera’s meter determines exposure. Remember that the camera’s spot and center-weight meter will expose all subjects, regardless of their tonality, as if they were middle tone. This means that snow will be rendered medium tone gray on film if the spot or center-weighted meter reading is used without adding +1 2/3 to + 2 stops of light. The camera’s matrix meter will meter a snow scene differently than a spot or center-weighted meter due to the sophisticated metering pattern and the extent of scenes in the camera’s data base. For matrix metering it is important to experiment with various snow scenes to understand when and how much compensation to use when photographing snow.

Just because winter offers some unique exposure challenges don’t put your camera away and take a three-month hiatus. By using the ten tips that follow this article, you should be able to overcome any other problems that may occur when photographing snow. All that’s left to do is to gear up and get outdoors this winter.