Dynamic Range And The Limits Of Photography

Things are never quite as we remember them. This is particularly true of photographs. Our minds seem to embellish the latent images of memory with richness and detail not found on screen or in print. Of course, a miniature, two dimensional version of a sprawling landscape can't compare to the real thing. But aside from size and depth, there is another element lacking in most photographs, the dynamic range or range of light found in a typical scene. The photographic medium is simply incapable of recording and displaying the wide range of highlights and shadows found in nature.

It turns out that the adaptive capability of human vision, allowing us to see sunlit snow as well as by starlight, has a dynamic range of more than 1,000,000:1. A typical sunlit scene might range 17 stops from the brightest clouds to the blackest shadows, or about a 100,000:1 dynamic range. The average digital camera, at the time of this writing, captures around 10 stops or a 1000:1 dynamic range. The very best prints, under good illumination, reflect a dynamic range of about 200:1. You see where this is going? The huge disparity between what we see, what we capture and what we show is one of the biggest reasons why our photographs don't look like what we remember.

Fortunately there are solutions or, more precisely, workarounds. The most obvious advice for avoiding blown highlights or blocked shadows is like a doctors advice: If it hurts when you do something, don't do it, don't shoot in the middle of a sunny day. High noon and sunshine is siesta time for professional photographers. Blue sky and sunshine, however, attracts photo enthusiasts the way a street lamp attracts moths. Yet it is precisely when clouds roll in and skies darken, when everyone else is heading home, that the soft palette of nature lends itself well to photography. So go against the flow, photograph on overcast days, particularly just before or after a gentle rain when the light is soft and colors are saturated.

If, however, you find yourself on the trail in the middle of a sunny day, there is still hope. For starters, resist the temptation for inclusiveness and crop large areas of either highlights or shadows out of your composition. Small, specular highlights or small shadows that go black aren't usually a problem and, in fact, can add to the sense of brilliance in a photograph. But large areas without detail, particularly overexposed skies, tend to ruin an image. One of the greatest new tools in digital photography is the ability to review your shot on the spot. The instant feedback is not only a great learning tool, but it allows you to recompose or re-expose while the opportunity is at hand. So check your images immediately after the shot to see if the highlights and shadows are acceptable. And carry extra battery.

Quite the opposite approach to avoiding high contrast scenes or cropping the extremes from your composition is to use the limited dynamic range of the camera to your advantage. This often takes the form of a silhouette against a bright and colorful background, as is common with sunrise and sunset photography. When shooting into the sun at sunrise or sunset, you are photographing a scene with an extreme dynamic range, well beyond what even the best cameras can record. One solution is to let the foreground go black and expose for the colorful highlights in the sky. The key to making this interesting is that the shape of the silhouetted foreground is recognizable. Distant mountains, a nearby tree, or even people, provide distinctive and interesting foregrounds. By exposing for the highlights and composing for the shadows, you can turn the limitations of your camera into a dramatic photograph.

There are, of course, other ways to work the tremendous dynamic range of nature within limits of photography, most notably graduated filters and high dynamic range imaging. But these are best covered separately, because they require additional equipment or software. With no more than a simple camera, however, it is possible to avoid the blown highlights and blocked shadows so common in nature photographs. By shooting on cloudy or even stormy days, all the color, detail and richness of nature's palette will be within your camera's range. On sunny, contrasty days, simply compose so that, at most, only small areas of the photograph have bright highlights or dark shadows. Finally, use the camera's limitations to your advantage and create dramatic or moody images by exposing for the highlights and composing for strong silhouettes. These techniques just might result in photographs that are better than what you remember.

Back To Composition And Visual Cues For Depth

Onward To Graduated Filters

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