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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20 Sep 08 Digital Camera Basics - Want To Stop Being An Idiot And Learn How Digital Cameras Work?
Author: Mike Singh
With the advancement of the digital camera and the software that is made for them, most pictures look professional from the first click of the camera. But like most things, it is important to understand the “how and why” for higher quality results.
The basics of a digital camera revolve around terms like pixel, pixel count, white balance, sensor, sensitivity, optical zoom, or digital zoom. These improve your understanding of what digital photography is all about, and will help you become a more efficient photographer.
For example, one important term is digital sensor. A typical digital camera may have a digital sensor element that is as big as a small finger nail. Most 5MP digital cameras use a sensor that is 7mm x 5mm in size. This is much smaller than the size of the negative of a 35 mm camera. However, high-end digital cameras have large sensors, and generate superior images. These are important things to know, to see how pictures can be better or worse.
Digital cameras also have sensitivity settings similar to ISO ratings on film. Most digital cameras will have settings for sensitivity equivalent to ISO 100 and ISO 200. Many also have a setting for ISO 400. A few expensive digital SLR cameras with large sensors have settings for ISO 3200 or even for ISO 6400.
Most digital cameras have an optical and a digital zoom. An optical zoom lens works by changing the focal length and magnification while the zoom is being utilized - with the image quality remaining high. Digital zoom works by cropping the image to a smaller size. The cropped image is enlarged to fill the frame, causing a significant loss of quality.
The manufacturers of digital cameras use the term “pixel count” to describe their camera’s image properties. The word pixel originates from “(PIC)ture (EL)ement”- with the use of phonics added for emphasis. It represents a single point in a graphic image - not a dot but an abstract sample that can be reproduced in any size, without a dot or square appearance.
A pixel is important to understand because it is the basic unit of measurement, used to define a digital photograph. The more the number of pixels per square inch, the higher the resolution of a digital picture, increasing its clarity. Some examples would be 2,400 pixels per inch, 640 pixels per line, or spaced 10 pixels apart. Designers, artists, and photographers sometimes interchange the pixel terminology, such as dots per inch (dpi) with pixels per inch (ppi). The dpi is used when it refers to the printer’s resolution for the printing density. Each pixel is made up of three color channels - red, green and blue-and has a numerical value of between 0 and 255.
The pixel count also decides the size of a print in case you want to print photographs. A 3MP camera can provide excellent 4×6 inch prints, while a 4 or 5MP digital camera can deliver high quality 8×10 inch prints. With a digital camera you can pick the white balance to suit the light source. This is meant to ensure that white looks white, and not yellow or blue. Normally, your digital camera will do this automatically. You can also set the white balance yourself for better effects.
Since each pixel generates three bytes of data, a photographer using a 3MP camera will need a storage space of 9 million bytes or 9MB to store a single image. This is a huge amount of space. Camera companies therefore allow for a compression of image using a format called JPEG. This reduces the file size significantly but while doing so a lot of data is lost. To overcome this problem companies have come up with different storage formats. Canon calls it RAW while Nikon calls it NEF. The data loss is less in these formats.
The low end cameras used by beginners can shoot images whose pixel count is one million is categorized as 1 MP or one million pixel camera because the intensity of each pixel is variable, with each pixel having three or four dimensions of variability - such as red, green and blue, cyan, magenta, yellow, and black. The high-end cameras used by professionals, can range from 14MP to 22MP with a pixel count as high as 14 million or 22 million per image.
The thing to remember is the higher the resolution, the more realistic the image is, matching closest what the actual image is. So take your time, do some research, and talk to people who know cameras. Otherwise, a lot of money will be spent on something that is barely adequate for what you want.
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