How do digital cameras work?

On the surface, many digital cameras could easily be mistaken for traditional cameras. Both have lens, viewfinders, zoom features, and various buttons and gadgets neatly packed into a square package.

However, even the smallest inspection of a digital camera would immediately demonstrate its place in twenty-first-century technology. Digital cameras rely on three unique components that set them apart from traditional photography devices: image sensor technology, memory storage, and advanced editing capacities.

The technology used to capture digital images makes it unnecessary for any formal development of pictures. The process begins with a device known as a charge-coupled device (CCD). The cells (or tiny units) inside of a CCD are known as photosites. These cells change the images captured by the camera into electric charges through a device called an analog-to-digital converter (ADC). This process works because the cells (photosites) contain an electric portion which attracts the voltages resulting from an image. These cells only attract light, so the color is something that must be added to the image at a later time.

Before the image reaches the ADC, it passes through another device known as a read-out register so that the image current can be amplified (or enhanced). Once the current passes through the ADC of the cells, it is then transferred to its next stop in the factory the digital signal processor (DSP). It is here that the image receives its touch-ups before it is ready for viewing.

The DSP tweaks the image’s contrast (lightness or darkness), brightness (intensity), and compression (amount of space it takes up in digital memory). Since most digital cameras contain an LCD panel, this is generally the last stop for an image before it is stored in memory. The panel allows the photographer to manually adjust the image on the camera before transferring it to a computer.

Color is added to the digital image through one of four methods. Since photosites are colorblind, sensors in the camera can only filter the three primary colors of the color spectrum. These three colors are mixed to produce other colors. In order to record the primary three (red, blue, and green), most cameras use either interpolation or a Bayer filter. Interpolation involves placing a filter over each photosite, breaking the sensor into blue, red, and green pixels.

A Bayer filter pattern alternates red and green filters with blue and green filters. (This method is used for less expensive cameras). Costlier cameras generally utilize either a spinning disk or a beam splitter. Spinning disks rotate red, blue, and green filters in front of a sensor, while beam splitters utilize three different sensors with three different filters. The camera records the three colors for later mixing.

Pixels are mentioned above, but what exactly are pixels? Images are stored in the camera as tiny dots called pixels. Each pixel contains one color out of possible millions. When one speaks of the resolution, this refers to the size of an image produced by the camera (sizes are measured in pixels). The more pixels an image can hold, the greater the quality in resulting pictures will be.

The amount of images that can be stored on a digital camera depends upon the capacity of the camera itself and what types of memory cards are used. Many memory cards will allow an image to be directly transmitted onto computer screens.

Once a photographer does decide to transfer his images onto a computer, then he has many more options for editing: color balance, cropping (cutting off unwanted edges of an image), scaling (making the image smaller or larger), etc. Any computer store will offer countless brands of software specifically designed for editing digital photos.

Most experts recommend saving digital images as JPEG files. Such files have a great variety of colors available for pictures, while they easily compress the images into smaller sizes without sacrificing the quality of the images.

The preceding information covers the technical basics of digital photography. Yet, as with any new venture, the best way to familiarize oneself with the unknown is practice, practice, and more practice.

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