21 Sep 08 The Technology Behind Digital Cameras
Author: Roberto Sedycias
Technology has revolutionized the concept of capturing live images. The earlier concept of producing permanent photograph was based on pure chemistry. In 1830, Louis Daguerre, devised the first practical way of producing permanent photographs. Today we are talking about the computerized photo imagery in the filmless picture taken by a device that is smart in electronic intelligence and in appearance - digital camera.
A digital camera takes video, still photographs, or both digitally. It records images on a light sensitive sensor. Instead of using a film, an arrangement of charged-coupled devices-light sensitive semiconductors, which stores electrical charges,-does the job. These digital sensors-composed of pixels -transform the light from the scene snapped into an analog signal which is then converted into a digital version. One electronic filtering system regulates color and other picture components. Another system reduces the picture. The image is finally sent to a temporary storage area and ultimately onto a memory card. Many compact digital cameras can record sound, video and still photographs.
The images are transferred to a computer where they can be modified, printed, attached to email, inserted in web pages, etc. The most significant advantages of a digital camera are its memory capacity and ability to screen the images taken on a tiny video monitor.
The technology of the digital camera relates to the same technology of Video Tape Recorder. The first VTR in 1951 captured images from the television by converting the information into electrical impulses (digital) and subsequently saving them onto magnetic tape. It was in 1960s when NASA had made a major breakthrough by converting analog to digital signals by means of the space probe for mapping the surface of the moon. Also digital imaging had its other uses in spy satellites.
Kodak scientists invented the first mega pixel sensor capable of recording 1.4 million pixels. In 1991, Kodak released the first digital camera system- a Nikon F-3 camera equipped with 1.3 megapixels aimed at journalists. The first digital camera for the consumers which worked with a home PC via a serial cable were the Apple Quick Take 100 camera(1994), the Kodak DC40 camera(1995), the Casio QV-11 with LCD monitor(late 1995) and Sony`s Cyber-Shot Digital Still Camera(1996).
The main features of a digital camera can be summarized as follows:
Resolution: Resolution means sharpness of a picture. The higher the number of pixels, the higher is the resolution.
Memory: The pictures are stored like a data file in a digital camera. The size of the memory determines the number of picture which can be taken, stored and downloaded in the computer.
Flash Type: Most digital cameras have a built in flash of a range around 10 -16 feet which is required to provide extra light needed to take photographs in insufficient light.
Optical Zoom: Normally two types of zoom lenses are used viz., digital and optical. The optical zoom lenses serve more purpose like adding detail and sharpness.
Compression: This process helps to reduce the file size.
Lens: The length of a lens determines how much of a scene will fit into a picture.
LCD Screen: A very interesting feature of a digital camera is the LCD screen which permits one to see what the photo will look like before and after taking photographs, leaving room to decide whether to erase or save the photo.
In the market there are several brands of digital camera which are selling successfully and the continuous improvement in Technology is leading way to introduction of more and more exciting features in the digital camera.
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21 Sep 08 Digital Camera - the Easy Way to Take Pictures
Author: Roberto Sedycias
In comparison to film cameras, digital cameras have number of advantages which includes displaying the image on the camera screen right after recording, a single small memory device can record thousands of images, records video with sound, provision to edit images, and above all storage capacity can be re-used by deleting the images. There are numbers of devices available that has in-built digital cameras like mobile phones, PDA`s etc. Specialized digital cameras are fit into astronomical devices like The Hubble Space Telescope.
Digitizing images on scanner and digitizing video signals are much older than making of still images using digital signals from an array of discrete sensor elements. It was then used for astronauts to provide onboard navigation information during their visit to planets. It provided the still photos of stars and planet locations during transit and also additional stadiametric information for orbiting or landing guidance while approaching planet.
Steven Sasson, an engineer at Eastman Kodak, attempted to develop first digital camera with solid state CCD image sensor chips. But it was just a technical exercise. The true digital camera was Fuji DS-1P developed in 1988. And the first commercialized camera was Dycam Model 1 in 1990. Then in 1991, Kodak launched its Kodak DCS 100. Else Casio QV-10 was the first consumer camera in 1995. Nikon D1, a 2.74 megapixel camera was the first digital SLR developed in 1999. And in 2003, Canon 300D, first 600 megapixel camera was launched.
There are various types of digital cameras available. For videos, there are professional video cameras which are used in television and movie production. Camcorders come with inbuilt microphone and a small liquid crystal display to watch video while recording and playback. One can get still photographs also with them. Webcams, attached to computers, can capture full-motion video and are also available with microphones or zooming ability.
In live-preview digital camera, there is an electronic camera that can be used to frame and preview before taking the photograph and also to review stored photographs. Many of such cameras can take motion pictures. Then the recorded images can be transferred to computer, printer or any other such device. USB mass storage device enables the camera to function as disk drive for computer and Picture Transfer Protocol is then used.
To use Firewire, storage device is removed from camera and inserted into other device. Compact digital cameras, small and portable with inbuilt flash, are easy to use, and images are stored using Lossy compression. They might be able to capture motion picture but that to a limit. Bridge or SLR like camera is higher-end-live-preview camera with more advanced features like superzoom lenses, takes movies with sound, etc. Digital rangefinder, a user operated mechanism, is capable to measure subject distance.
Apart from above mentioned digital cameras, there are other categories also. Professional modular digital camera systems are used in studios for commercial production. Line-scan camera systems, based on focusing mechanism, are used in industrial settings to capture images of constantly moving materials. They capture images at extremely fast with high image resolutions.
Most of the digital cameras come with pre-set modes for different applications. Data can be transferred through USB port, Firewire port, USB PTP mode and even through wireless connections like WiFi, Bluetooth etc. These data are mostly stored in Microdrives, Joint Photography Experts Group (JPEG), Tagged Image File Format (TIFF) and RAW. Formats for movies are AVI, DV, MPEG and MOV. Recently MP4 format is also developed. Digital cameras have small but powerful batteries to operate for enough length of time.
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