Digital still camera


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Digital still camera

  1. 1. Digital still camera
  2. 2. History • Steven Sasson as an engineer at Eastman Kodak invented and built the first electronic camera using a charge-coupled device image sensor in 1975. Earlier ones used a camera tube; later ones digitized the signal.
  3. 3. Definiton • A digital still camera is a camera that encodes digital images and videos digitally and stores them for later reproduction. • Digital and film cameras share an optical system, typically using a lens with a variable diaphragm to focus light onto an image pickup device.
  4. 4. Image sensors • The resolution of a digital camera is often limited by the image sensor (typically a CCD or CMOS sensor chip) that turns light into discrete signals • The brighter the image at a given point on the sensor, the larger the value that is read for that pixel. • single-shot capture systems use either one sensor chip with a Bayer filter mosaic, or three separate image sensors • multi-shot exposes the sensor to the image in a sequence of three or more openings of the lens aperture. • The third method is called scanning because the sensor moves across the focal plane much like the sensor of an image scanner.
  5. 5. Types of digital cameras Digital compact cameras • Compact cameras are intended to be portable and are particularly suitable for casual "snapshot". • Most, apart from ruggedized or waterresistant models, incorporate a retractable lens assembly that provides optical zoom. The auto actuating lens cover protects the lens from elements.
  6. 6. Types of digital cameras Bridge cameras • Bridge are higher-end digital cameras that physically resemble DSLRs and share with them some advanced features, but share with compacts the use of a fixed lens and a small sensor. • Like compacts, most use live preview to frame the image. • Their autofocus uses the same contrast-detect mechanism, but many bridge cameras have a manual focus mode, in some cases using a separate focus ring, for greater control .
  7. 7. Types of digital cameras Mirrorless interchangeable-lens camera • In late 2008, a new type of camera emerged, which uses larger sensors and offers lens interchangeability. • These are simpler and more compact than DSLRs as they do not have the lens reflex system.
  8. 8. Types of digital cameras Digital single lens reflex cameras • Digital single-lens reflex cameras (DSLR) uses mirror to direct light from the lens through a separate optical viewfinder. • The mirror is moved out of the way to direct the image to the sensor at the time of exposure.
  9. 9. Connectivity • Many digital cameras can connect directly to a computer to transfer data. • Many modern cameras support the PictBridge standard, which allows them to send data directly to a PictBridge-capable computer printer without the need for a computer. • Many digital cameras include a video output port. Usually sVideo, it sends a standard-definition video signal to a television, allowing the user to show one picture at a time.
  10. 10. Image data storage • Many camera phones and most stand alone digital cameras use removable flash memory card to store image data. The majority of cards for separate cameras are SD format. • Onboard flash memory — Cheap cameras and cameras secondary to the device's main use (such as a camera phone) • PC Card hard drives — early professional cameras (discontinued) • Thermal printer — known only in one model of camera that printed images immediately rather than storing
  11. 11. Batteries • Digital cameras have become smaller over time, resulting in an ongoing need to develop a battery small enough to fit in the camera and yet able to power it for a reasonable length of time. • Digital cameras utilize either proprietary or standard consumer batteries.
  12. 12. File formats • The Joint Photography Experts Group standard (JPEG) is the most common file format for storing image data. Other file types include Tagged Image File Format (TIFF) and various Raw image formats. • Many cameras, especially high-end ones, support a raw image format. A raw image is the unprocessed set of pixel data directly from the camera's sensor, often saved in a proprietary format. Adobe Systems has released the DNG format, a royalty-free raw image format used by at least 10 camera manufacturers.
  13. 13. Thanks for your attention!