Digital Photography - Image Sensors (original) (raw)

A digital file is data, no different to any other computer file. It can be saved to any computer storage media. The file can also be copied and recopied without any loss of quality. Copies can be kept in more than one picture library, or in other locations, all giving high-quality images. Image files can be opened on a computer using imaging software such as Adobe Photoshop. This allows dust spots and other minor blemishes to be removed quickly and easily. It is also possible to make more significant changes to an image, but this may not be acceptable in areas such as news, sport and wildlife. Almost all newspapers, magazines, books, brochures and other printed materials are now created on computers and use digital image files for their photographs. To meet this demand, most picture libraries now only accept digital images. Although it is possible to scan film transparencies to create digital files, it is more convenient to shoot digitally in the first place. The term analog refers to simple or SLR cameras, which uses film as the printing medium for photographs. They are then produced in analog, using a chemical process. Film cameras have the advantage of being relatively inexpensive as compared digital cameras of the same quality, but on the other hand, buying film and developing rolls can get expensive. Analog cameras have 35 mm film; hence light covering a bigger area than in digital cameras. The main disadvantage of an analog camera is for beginners; they would need to note down the camera settings, before actually taking pictures. Different effects on pictures, which result from developing, also need to be tracked. The most important advantage of an analog camera, the reason why most photographers choose it, is the picture quality. The picture quality that can be achieved with a film camera is very high and the images turn out extremely sharp. The reason behind this is the chemical reaction which takes place when light from the shutter falls on the film, and as a result an exact, crisp and inverted i.e. negative representation of the object is obtained. This is not possible with a digital camera. Digital photography is no different from film/analog photography, as matter of fact the technique and style used is the same, except for one aspect. The distinction between digital and analog photography is that traditional film is replaced by a charged coupled device (CCD), which contains tiny grids containing millions of photosensitive elements. When a picture is clicked, a ray of light falls on the photosensitive elements, which then registers a specific intensity of light, as an electrical charge. The electrical charges are then passed onto an analog-to-digital converter that transforms them into digital data. To determine the actual color value of any one pixel, the camera's software makes a calculated guess based on the values registered by three neighboring photosensitive elements. This is the reason which accounts for the reduction the image's level of detail, and eventually translates into the quality of image. Image Sensor An image sensor or imaging sensor is a sensor that detects and conveys the information that constitutes an image. It does so by converting the variable attenuation of waves (as they pass through or reflect off objects) into signals, the small bursts of current that convey the information.