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| Aperture | The opening in a lens that admits light. This opening regulates the amount of light passing through the lens. This is expressed as an f-number: f/8, f/11, and so on. |
| aperture-priority | A mode of automatic exposure in which the photographer selects the aperture and the camera sets the shutter speed that will produce the correct exposure. |
| automatic exposure | A system that automatically sets correct exposure by linking a camera’s exposure meter with the shutter or aperture or both |
| available light | The light that already exists (natural or artificial) where a photograph is to be made, as opposed to light brought in by the photographer.. Also called ambient light or existing light. |
| Bit | The smallest unit of information usable by a computer |
| brightness | Strictly speaking, a subjective impression of the lightness of an object. The correct term is luminance. |
| byte | A unit of digital data containing eight bits.. |
| depth of field | The zone of acceptable sharpness in a picture, extending in front of and behind the plane of the subject, that is most precisely focused by the lens.. If you decrease the size of the aperture, the depth of field increases |
| exposure | 1. The act of letting light fall on a light-sensitive material. 2. The amount of light that passes through a lens onto a light-sensitive material to form an image. In the camera, too much light causes overexposure. Underexposure (too little light). |
| f-number/ f-stop | The number resulting when the focal length of a lens is divided by the diameter of the aperture.. The f-numbers become progressively higher as the aperture is reduced to allow in less light; i.e. f/5.6, f/8, f/11, f/16, f/22 |
| focus | 1. The position at which rays of light from a lens converge to form a sharp image. |
| kilobyte | A unit of digital data containing 1024 bytes. Used to describe the size of a computer file. |
| lens | An optical device made of glass or other transparent material that forms images by bending and focusing rays of light.. The size, curvature and positioning determine the focal length and angle of view of a lens. |
| manual exposure | A non automatic mode of camera operation in which the photographer sets both the shutter speed and the aperture. |
| megabyte | A unit of digital data containing 1,048,576 bytes. Used to describe the size of a computer file. |
| overexpose | To give more than normal exposure to film or paper. The resulting silver density is often too great for best results. |
| PC terminal | The socket on a camera or flash unit into which a PC connector (sync cord) is inserted. |
| pixel | Short for picture element. The smallest unit of a digital image that can be displayed, changed, or stored. |
| programmed automatic | A mode of automatic exposure in which the camera sets both the shutter speed and the aperture that will produce the correct exposure |
| shutter | The camera mechanism that controls the duration of the exposure. |
| shutter-priority | A mode of automatic exposure in which the photographer selects the shutter speed and the camera sets the aperture that will produce the correct exposure. |
| tripod | A three-legged support for a camera. The legs (usually collapsible) are hinged to a head to which the camera is attached, and usually moveable. |
| underexpose | To give less than normal exposure to film or paper. The resulting silver density is often less than necessary for best results. |
| the Elements of Design | line, color, shape, form, texture. pattern |
