Digital cameras capture light to create an image. They contain a lens to focus the light, a sensor to measure the light, and an image processor to interpret the image. Cameras also contain an aperture to control the amount of light, a shutter to control the amount of time the light is allowed to enter, and a viewfinder to preview the image. Many digital cameras also include an LCD screen for viewing images and a memory card for storing them. Additionally, some cameras have additional features such as a built-in flash, filters, and zoom capabilities.