The term digital still camera (DSC) most commonly refers to the class of live-preview digital cameras, cameras that use an electronic screen as the principal means of framing and previewing before taking the photograph. All use either a charge-coupled device (CCD) or a CMOS image sensor to sense the light intensities across the focal plane.
Many modern live-preview cameras have a movie mode, and a growing number of camcorders can take still photographs. However, even a low-end live-preview camera can take better still pictures than a mid-range video camera, and mid-range live-preview cameras have much lower video quality than low-end video cameras; that is, products are not generally optimized for both still and video photography, due to their different requirements.
Among live-preview cameras, most have a rear liquid crystal display for both preview and reviewing photographs. Transfers to a computer are commonly carried out using the USB mass storage device class (so that the camera appears as a drive) or using the Picture Transfer Protocol (PTP) and its derivatives; in addition, Firewire is sometimes supported.
The live-preview cameras are typically divided into compact (and subcompact) and bridge cameras.