Glossary Ambient light: The available, or existing, light that naturally surrounds a scene. Aperture: The size of the opening in the iris of a lens. Apertures are designated by f-numbers. The smaller the f-number, the larger the aperture and the more light that hits the sensor. Bracket: To shoot more than one exposure at different exposure settings. Chiaroscuro: Moody lighting that shows contrasts between shadows and brightness. Color space: A color space—sometimes called a color model—is the mechanism used to display the colors we see in the world in print or on a monitor. CMYK, LAB, and RGB are examples of color spaces. Composite: Multiple images that are combined to create a new composition. CMYK: Cyan, Magenta, Yellow, and Black; the four-color color model used for most offset printing.
Extension tube: A hollow ring that fits between a lens and the DSLR, used to achieve closer focusing. f-number, f-stop: The size of the aperture, written f/n, where n is the f-number. The smaller the f-number, the larger the opening in the lens; the larger the f-number, the smaller the opening in the lens. Focal length: Roughly, the distance from the end of the lens to the sensor. (The relationship of focal length to sensor size is explained on page 234.) Framing: In a photographic composition, positioning the image in relationship to its edges.
Depth-of-field: The field in front of and behind a subject that is in focus.
Grain: Texture found in photographic film and prints due to the residue of small grains of metallic silver left over from chemical developing.
Diffraction: Bending of light rays; unwanted diffraction can cause loss of optical sharpness at small apertures.
Grayscale: Used to render images in a single color from white to black; in Photoshop a grayscale image has only one channel.
DSLR: Digital Single Lens Reflex, a camera in which photos are composed through the lens that will be used to take the actual image.
Hand HDR: The process of creating a HDR (High Dynamic Range) image from multiple photos at different exposures without using automatic software to combine the photos.
Duotone: A historic printing process that created rich monochromatic imagery using two colors or inks—with black being one of the colors. Each color was used to ink a separate plate that were combined in register.
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Exposure histogram: A bar graph displayed on a camera or computer that shows the distribution of lights and darks in a photo.
High Dynamic Range (HDR) image: Extending an image’s dynamic range by combining more than one capture either using automated software or by hand.
Dynamic range: The difference between the lightest tonal values and the darkest tonal values in a photo.
High key: Brightly lit photos that are predominantly white, often with an intentionally “over exposed” effect.
Exposure: The amount of light hitting the camera sensor. Also the camera settings used to capture this incoming light.
Hyperfocal distance: The closest distance at which a lens at a given aperture can be focused while keeping objects at infinity in focus.
Creative Black & White