I recently took a trip up to Northern Canada to photograph a variety of owls, and came away happy – if not chilled to the bone. It’s cold up above the 51st parallel, no matter the time of day. That didn’t seem to impact the hunting owls of the region, who’s keen senses can detect rodents beneath the snowfall dozens of meters away. They essentially do a graceful face plant into the snow, rummage around, and come away with a snack.
The light sky and the bright white snowy landscape make shooting a challenge. To control the light and capture a quality image, one first has to understand light in terms of it’s relationship to photography. This excerpt from “Chapter 6: Reading the Light” from The New Art of Photographing Nature explains it more succinctly than I might in a blog ramble:
Without light we would have no color. And without light, there would be no photography. In fact, the word photography derives from Greek roots meaning “writing with light.”
Primitive man did not have the benefit of science to explain natural phenomena such as the rainbow. Nor did we, until Sir Isaac Newton’s use of the prism separated white light into its component colors. Light is a form of electromagnetic energy, which, in the whole spectrum of frequencies, is only visible as colors in a very narrow band. Other frequencies, such as infrared, ultraviolet, gamma, and X-ray radiation, are invisible to our eyes.
Yet, despite our basic understanding of light, it is something we are apt to take for granted, like the rising and setting of the sun. But in photography, we can never take light for granted, and must learn to perceive it many nuances. The quality of the light creates a variety of colors and moods. Light also models form, and the direction of light is crucial to how we perceive shape and depth in the landscape.
When talking about light, it is important to distinguish between quality and quantity. Quality of light can, for the outdoor photographer, mean the time of day, the angle of the light striking your subject or whether it creates high-contrast or low-contrast conditions. It can also be measured as color temperature (in degrees Kelvin) with daylight on a sunny day being around 5500 degrees Kelvin. While color film required filtration to correct for changes in color temperature, digital cameras have a built-in white balance function that can adjust the camera to virtually any lighting condition, indoors or out.
Quantity of light refers simply to the amount of light reaching the camera’s sensor and recording an image. It is by controlling this light, through changes in aperture and shutter speed, that we arrive at a proper exposure.