ambient light In any scene ambient is natural light.
aperture An opening within the lens that controls how much light reaches the sensor. Apertures come in f-stops, such as f/5.6 or f/22. Each successive f-stop, as the number goes up, decreases the light reaching the sensor by half. Aperture also affects exposure and depth of field. The lower the aperture number, the faster the lens.
Aperture Priority mode An automatic mode available in most dSLR cameras in which you choose the aperture and the camera chooses the correct shutter speed.
artifacts Unwelcome visual distortions in an image, such as blooming, chromatic aberrations, noise, and JPEG compression.
aspect ratio A measurement of the relation between ...