Manufacturers : Cameras and optics : Digital cameras

Digital cameras are devices used to convert optical images into digital image data through an imaging device, such as a CCD image sensor, and record the image data as an image file on a storage medium, such as a memory card. Digital cameras use image sensor technology and memory storage for capturing and storing images in a digital format. The digital format allows images to be available instantly with no need for a chemical development process necessary for a conventional camera using light-sensitive films. A typical digital camera shoots a subject with a solid image pickup device such as an image pickup device including a charge coupled device (CCD) or CMOS (complimentary metal-oxide semiconductor) sensors, and obtains image data including a still image and/or a motion image. The digital sensor array, charge-coupled device (CCD) array, has a large number of photosensitive elements arranged in a regular pattern. A digital camera normally has color filters for individual pixels of the CCD so that the image information is separated into R (red), G (green) and B (blue) color data by means of these color filters, and then sensed. The light energy is transferred into electrical signals by the CCD. The electrical signals are then converted into digital signals through analog/digital conversion and stored in a memory. The number of pictures a user may take is limited by the size and type of memory included in the digital camera. Once the camera memory is full, it can be downloaded to a personal computer or other device and the pictures are deleted from the camera.

General digital cameras are configured to be able to load a removable recording medium for recording and storing captured images. These recording mediums include memory cards incorporating a flash memory having a capacity of approximately several tens of M bytes, floppy disks,  and small-sized hard disks. One known memory card is CompactFlash available from SanDisk Corporation. CompactFlash cards are based on flash memory technology and provide non-volatile storage of digital images. Another known removable memory storage is a Smart Media card (also known as SSFDC, solid state floppy disk card) available from Toshiba Corporation. Smart Media cards are smaller and lighter than compact flash cards. Small hard disk drives, known as microdrives, are also used as storage medium. The microdrives have much higher capacity than flash memory but consume substantially more space and power. The removable storage devices are on rapid increase in their capacity. Today, they can store increased amount of image data as compared to that several years before.

In digital cameras, the viewing of the scene that will be captured is accomplished with either an optical viewfinder or a liquid crystal display (LCD) unit in combination with an optical viewfinder. The liquid crystal display is used both to display a playback of an image shot and stored previously and to display an image just being shot. This enables the user to determine picture composition and confirm focus condition while viewing the image just being shot. Digital cameras equipped with an optical viewfinder divide into a separate type, in which light is introduced to the viewfinder without being passed through a taking lens, and a single-lens-reflex (SLR) type, in which the light having passed through a taking lens is reflected so as to be introduced to the viewfinder. A digital camera typically contains an on-board processor, which can be programmed to perform a variety of functions. The processor can be programmed to embed supplementary information in the digital image.Some digital cameras are provided with a sound memo function for recording sounds or voices as a sound data file in association with an image file, or a voice recorder for recording sounds as a sound data file independently of image data.