Digital photography that uses an array of light sensitive sensors to capture the image focused by the lens,as opposed an exposure on light sensitive film.The captured image is then stored as a digital processing(colour correction,sizing,cropping etc),viewing or printing.Until the advent of such technology,photographs were made by exposing light sensitive photo film,& used chemical photographic processing to develop & stabilize the image.By contrast,digital photographs can be displayed,printed,stored,manipulated,transmited and archived using digital and computer techniques ,without chemical processing.
Advantages of professional digitalcameras• Immegiate image review & deletion is possible,lighting & composition can be assessed immediatily,which ultimately conserves storage space.• Faster workflow:Management(colour & file),manipulation & printing tools are more versatile then convention film processes.However,batch processing of RAW files can be time consuming ,even on fast computer.
Disadvantages of digitalcameras• Whereas film camerascan have manual backups for electronic and electrical features, digital cameras are entirely dependent on an electrical supply (usually batteries but sometimes power cord when in tethered mode).• Many digital sensors have less dynamic range than color print film. However, some newer CCDs such as Fujis Super CCD, which combines diodes of different sensitivity, have improved uWhen highlights burn out, they burn to white without details, while film cameras retain a reduced level of detail, as discussed aboveon this issue.
Equivalent features• Image noise / grainNoise in a digital cameras image is remarkably similar to film grain in a film camera. At high ISO levels (film speed) the grain/noise becomes more apparent in the final image. Although film ISO levels can be lower than digital ISO levels (25 and 50 respectively), digital settings can be changed quickly according to requirements, while film must be physically replaced and protected from all light during such replacement. Additionally, image noise reduction techniques can be used to remove noise from digital images and film grain is fixed. From an artistic point of view, film grain and image noise may be desirable when creating a specific mood for an image. Modern digital cameras have comparable noise/grain at the same ISO as film cameras. Some digital cameras though, do exhibit a pattern in the digital noise that is not found on film
Speed of use• Previously digital cameras had a longer start-up delay compared to film cameras, i.e., the delay from when they are turned on until they are ready to take the first shot, but this is no longer the case for modern digital cameras with start-up times under 1/4 second (0.15 seconds for the Nikon D90). Similarly, the amount of time needed to write the data for a digital picture to the memory card is now comparable to the amount of time it takes to wind the film on a film camera, at least with modern digital cameras and modern fast memory cards. Both digital cameras and film cameras have a small delay between when the shutter button is pressed and when the picture is taken – this is the time necessary to autofocus the lens and compute and set the exposure. (This shutter delay is practically zero for SLR and the best DSLR cameras.)
Frame rate• The Nikon D3 can take still photographs at 11 frames per second; the fastest film SLR could shoot 14 frames per second (Canon F1-n with a super high speed motor, but fewer than 100 were constructed for the 1984 Summer Olympics). The Nikon F5 is limited to 36 continuous frames (the length of the film) while the Canon EOS-1D Mark III is able to take about 110 high definition JPEG images before its buffer must be cleared and the remaining space on the storage media can be used. Even Bridge camera such as Fujifilm FinePix HS10 has burst mode 10 frame/s and Panasonic Lumix DMC-FZ100 has 11 frame/s. Moreover FinePix HS10 can take movies at 1000 frame/s at 224x64 pixels with no sound.
Image longevity• Film and prints can fade, but digital images can potentially last unchanged forever. However, the media on which the digital images are stored can decay or become corrupt, leading to a loss of image integrity. Film and digital media should be stored under archival conditions for maximum longevity. Without backup it is easier to lose huge amounts of digital data, for example by accidental deletion of folders, or by failure of a mass storage device. In comparison, each generation of copies of film negatives and transparencies is degraded compared to its parent. Film images can easily be converted to digital (by using a digital film scanner for example) with some possible loss of quality.
Colour reproduction• Colour reproduction (gamut) is dependent on the type and quality of film or sensor used and the quality of the optical system and film processing. Different films and sensors have different color sensitivity; the photographer needs to understand his equipment, the light conditions, and the media used to ensure accurate colour reproduction. Many digital cameras offer RAW format (sensor data), which makes it possible to choose color space in the development stage regardless of camera settings; in effect, the scene itself is stored as far as the sensor allows, and can to some extent be "rephotographed" with different color balance, exposure, etc. Although RAW format can be used, the sensor and the cameras dynamics can only capture in the GAMUT that the system will allow, and when that image is transferred for reproduction on any device, the best possible gamut that the person viewing the image will see is the gamut of the end device. For a monitor, it would be the screens gamut. For a photographic print, it will be the gamut of the device that printed the image on the paper.
Market impact• In late 2002, 2 megapixel cameras were available in the United States for less than $100, with some 1 megapixel cameras for under $60. At the same time, many discount stores with photo labs introduced a "digital front end", allowing consumers to obtain true chemical prints (as opposed to ink-jet prints) in an hour. These prices were similar to those of prints made from film negatives. However, because digital images have a different aspect ratio than 35 mm film images, people have started to realize that 4x6 inch prints crop some of the image off the print. Some photofinishers have started offering prints with the same aspect ratio as the digital cameras record.
Social impact• Throughout the history of photography, technological advances in optics, camera production, developing, and imaging have had an effect on the way people view images. Up until 1960, most printed photographs were black and white. Cameras that could print colour film began to be popular in the 1960s, particularly with the introduction of the Polaroid camera invented by Edwin Land, which could print out a colour film print directly from the camera, within a few minutes of taking the picture. Up until the advent of the digital camera, amateur photographers could either buy print film for their camera, or slide film. If they purchased slide film, the resulting slides could be viewed using a slide projector. Digital photography began to be available in the early 2000s. The simultaneous increased use of the Internet and email, relatively cheap computers and digital cameras led to a tremendous increase in the number of photographic images in digital formats
Recent research and innovation• Research and development continues to refine the lighting, optics, sensors, processing, storage, display, and software used in digital photography. Here are a few examples.• 3D models can be created from collections of normal images. The resulting scene can be viewed from novel viewpoints, but creating the model is very computationally intensive. An example is Microsofts Photosynth, which provides some models of famous places as examples.• High dynamic range cameras and displays are commercially available. Sensors with dynamic range in excess of 1,000,000:1 are in development, and software is also available to combine multiple non-HDR images (shot with different exposures) into an HDR image.• Motion blur can be dramatically removed by a flutter shutter (a flickering shutter that adds a signature to the blur, which postprocessing recognizes). It is not yet commercially available.
Applications and considerations• With the acceptable image quality and the other advantages of digital photography (particularly the time pressures of daily newspapers) the majority of professional news photographers capture their images with digital cameras.• Digital photography has also been adopted by many amateur snapshot photographers, who take advantage of the convenience of sending images by email, placing them on the World Wide Web, or displaying them in digital picture frames. The majority of cameras are camera phones integrated into cell phones but their usual small, poor quality lenses and sensors render most of them unsuitable for making even moderate size prints.