Glossary

Botanical Terms

Anther: The portion of the stamen that provides pollen.

Filament: The stalk in the stamen holding up the anther.

Genus: A family of plants in the Linnaean taxonomy, containing one or more species.

Ovary: Contains one or more ovules in a placental membrane; each ovule contains an egg that when fertilized becomes a seed.

Pistil: Female sexual organ of a flower, usually comprised of a stigma, style, and ovary.

Pollen: Carries sperm cells during the process of their movement between a stamen to the pistil of a flower.

Species: A basic unit of classification, and a taxonomic rank. Members of a species are often defined by whether they can reproduce with each other.

Stamen: Male sexual organ of a flower, usually comprised of an anther and a filament. Most flowers have multiple stamens.

Stigma: Sticky portion of the pistil used to receive pollen; where seeds germinate.

Style: Within the pistil, the stalk connected to the ovary that supports the stigma.

Taxonomy: A hierarchical scheme for grouping and categorizing; the Linnaean taxonomy established a biological classification system for organisms that is a way of ordering plants, including flowers.

Photographic Terms

Adobe Camera Raw (ACR): Used to convert RAW files into files that Photoshop can open.

Ambient light: The available, or existing, light that naturally surrounds a scene.

Aperture: The size of the opening in the iris of a lens. Lens apertures are designated by f-numbers. The smaller the f-number, the bigger the opening, and the less depth of field.

Blending mode: Determines how two layers in Photoshop will combine.

Bracketing: Shooting many exposures at a range of settings. It often works better to bracket shutter speed rather than aperture.

Brush tool: Used to paint on a layer or layer mask in Photoshop.

Channel: In Photoshop, a channel is a grayscale representation of color (or black) information. In RGB color there are three channels: Red, Green, and Blue.

Chiaroscuro: Moody lighting that shows contrasts between shadows and brightness.

Close-up filter: A piece of optical glass that screws into the front of a lens and provides magnification.

CMYK: Cyan, Magenta, Yellow, and Black. The four-color color model used for most offset printing.

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.

Curve: An adjustment used to make precise color corrections.

Depth of field: The field in front of and behind a subject that is in focus.

Diffraction: Bending of light rays; unwanted diffraction can cause loss of optical sharpness, particularly at small apertures.

DSLR: Digital single lens reflex camera.

Dynamic range: The difference between the lightest tonal values and the darkest tonal values in a photo.

Effective aperture: The aperture recorded by EXIF data as opposed to the aperture set on the camera. In close focus, the effective aperture is often a smaller opening than the set aperture.

EV (Exposure Value): Denotes any combination of aperture, shutter speed, and ISO that yields the same exposure. –1 EV means halving the exposure, and +1 EV means doubling the exposure.

Exposure: The amount of light hitting the camera sensor. Also the camera settings used to capture this incoming light.

Exposure histogram: A bar graph displayed on a camera or computer that shows the distribution of lights and darks in a photo.

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 sensor’s position is also called the focal plane. The location of the focal plane (the distance from which focal length is measured) is indicated on most camera bodies with a special symbol: . The horizontal line in the symbol indicates the position of the focal plane, used for determining the focal length when it is needed precisely.

Focus stacking: Extending the field of focus beyond that possible in a photo by combining multiple photos, each photographed at a different point of focus.

Gradient: A gradual blend, often used when working with layer masks in Photoshop.

Grayscale: Used to render images in a single color from white to black; in Photoshop a grayscale image has only one channel.

Hand-HDR: The process of creating an HDR image from multiple photos at different exposures without using automatic software to combine the photos.

HDR: Extending the dynamic range in an image using techniques including multi-RAW processing, hand-HDR, and automated HDR software.

High key: Brightly lit photos that are predominantly white, often with an intentionally “overexposed” effect.

Histogram: A graph that represents a distribution of values; an exposure histogram is used to display the distribution of lights and darks in an image.

Hyperfocal distance: The closest distance at which a lens at a given aperture can be focused while keeping objects at infinity in focus.

Image stabilization: Also called vibration reduction, this is a high-tech system in a lens or camera that attempts to compensate for, and reduce, camera motion.

In-camera multiple exposure: Exposures made on a single captured frame in the camera, and blended in the camera.

Infinity (∞): The distance from the camera that is far enough away so that any object at that distance or beyond will be in focus when the lens is set to infinity, regardless of aperture.

Inversion: A Photoshop adjustment that inverts the color in a channel or channels.

ISO: Scale used to set a camera’s sensitivity to light.

JPEG: A compressed file format for photos that have been processed from an original RAW image.

LAB color: A color model consisting of three channels. See page 258.

Layer: Photoshop documents are composed of layers stacked on top of each other.

Layer mask: Masks are used to selectively reveal or hide layers in Photoshop.

Lensbaby: A special purpose lens with a flexible barrel that allows you to adjust the “sweet spot” (area in focus).

Low key: Dimly lit photos that are predominantly black, often with an intentionally “underexposed” effect.

Macro lens: A lens that is specially designed for close focusing; often a macro lens focuses close enough to enable a 1:1 magnification ratio, so that the image on the sensor is as large as the image in real life.

Magnification ratio: The correspondence of an object and its actual size on the sensor.

Monochrome, monochromatic: A monochrome image is presented as nominally consisting of tones from white to black; however, “black and white” images can be tinted or toned, and usually vary from straight grayscale.

Multi-RAW processing: Combining two or more different versions processed from the same RAW file to extend the dynamic range and create a more pleasing final image.

Open up, open wide: To open up a lens, or to set the lens wide open, means to set the aperture to a large opening, denoted with a small f-number.

Overexpose: An overexposed photo appears too bright; the exposure histogram is bunched toward the right side.

Pre-visualization: Understanding, or seeing in one’s “mind’s eye,” before making an exposure how an image will come out after capture and processing.

Proper exposure: A proper, or correct, exposure is an exposure that is theoretically correct for a given subject based on overall or average light readings. With a proper exposure, the histogram is often thought of as a bell-shaped curve in the middle of the graph. Sometimes compared and contrasted with a “creative” exposure, which is used for creative purposes, but may appear too dark or bright in some or all portions of an image.

RAW: A digital RAW file is a complete record of the data captured by the sensor. The details of RAW file formats vary among camera manufacturers.

RGB: Red, Green, and Blue; a three-color color model, used for displaying photos on the web and on computer monitors.

Sensitivity: Set using an ISO number; determines the sensitivity of the sensor to light.

Shutter speed: Shutter speed is not a speed. Rather, it is the duration of time that the shutter is open. This interval of time controls how objects in motion are rendered.

Stop down: To stop down a lens means to set the aperture to a small opening; denoted with a larger f-number.

Tinting: Adding color to a monochromatic image.

Tonal range: The range of color and light and dark values in an image.

Toning: In the chemical darkroom, toner such as sepia or selenium was added for visual effect; in the digital darkroom, toning simulates the impact of chemical toning.

Underexpose: An underexposed photo appears too dark; the exposure histogram is bunched toward the left side.

X-Ray: Radiation shorter in wavelength than visible light.