Understanding the physics of light is essential for capturing great photographs. While there’s much more to light than what meets the eye, our eyes see more light than our cameras do. The amount of light that our eyes can convert into nerve impulses is limited, and our cameras capture even less light on their sensors.
One important concept to understand is dynamic range. On a bright day, our eyes can see details in both the bright highlights of the sky and the deep shadows on the ground simultaneously. However, cameras have a limited dynamic range and struggle to capture the same range of tones. Advances in sensor technology have improved dynamic range, allowing modern cameras to capture both highlights and details in darker areas.
The visible spectrum, which encompasses the colors we see, is only a small portion of the entire electromagnetic spectrum. It’s remarkable that we can differentiate all seven colors of the spectrum within a narrow range of 320 nanometers. Our atmosphere filters out harmful ultraviolet light, allowing us to experience the colors without harm.
Bending of light, called refraction, occurs when light passes through the atmosphere, allowing us to see the sun before it physically rises above the horizon. Each color of the spectrum has a different wavelength and travels at a different speed, causing the colors to bend at different angles. This dispersion of light is what creates rainbows and the colors we see in everyday life.
In photography, too much refraction and dispersion can result in unwanted effects like chromatic aberration. Lens manufacturers use multiple glass elements to minimize these aberrations and ensure that light converges on a single point on the sensor.
Diffraction, which occurs when light hits an edge, is another important concept. The smaller the aperture in photography, the more pronounced the diffraction becomes, leading to a decrease in image sharpness.
By understanding these principles of light, photographers can make informed decisions and capture stunning images.
