A digital camera is a camera that takes video or still photographs by recording images on an electronic image sensor. Most cameras sold today are digital, and digital cameras are incorporated into many devices ranging from mobile phones to vehicles. Digital cameras contain an optical system, typically using a lens with a variable diaphragm to focus light onto an image pickup device. The diaphragm and shutter admit the correct amount of light to the imager, Digital cameras can display images on a screen immediately after being recorded, and store and delete images from memory. Most digital cameras can also record moving video with sound. Some digital cameras can crop and stitch picture and perform other elementary image editing.