1. How digital cameras work The Exposure The big difference between traditional film cameras and digital cameras is how they capture the image. Instead of film, digital cameras use a solid-state device called an image sensor, usually a charge-couple device (CCD). On the surface of each of these. fingernail-sized silicon chips is a grid containing hundreds of thousands or millions of photosensitive diodes called photosites, photoelements, or pixels. Each photosite captures a single pixel in the photograph to be.

2. How digital cameras work When you press the shutter release button of a digital camera, a metering cell measures the light coming through the lens and sets the aperture and shutter speed for the correct exposure. For a digital camera when the shutter opens briefly, each pixel on the image sensor records the brightness of the light. Pixels capturing light from highlights in the scene will have high charges. Those capturing light from shadows will have low charges. When the shutter closes to end the exposure, the charge from each pixel is measured and converted into a digital number. The series of numbers can then be used to reconstruct the image by setting the color and brightness of matching pixels on the screen or printed page.

3. How digital cameras work

4. What is color? It may be surprising, but pixels on an image sensor can only capture brightness, not color. They record only the gray scale-a series of 256 increasingly darker tones ranging from pure white to pure black. How the camera creates a color image from the brightness recorded by each pixel is an interesting story. Colors in a photographic image are usually based on the three primary colors red, green, and blue (RGB). This is called the additive color system because when the three colors are combined or added in equal quantities, they form white. This RGB system is used whenever light is projected to form colors as it is on the display monitor (or in your eye).

5. How digital cameras work Since daylight is made up of red, green, and blue light, placing red, green, and blue filters over individual pixels on the image sensor can create color images. On many image sensors, there are twice as many green filters as there are red or blue filters. That's because a human eye is more sensitive to green than it is to the other two colors so green's color accuracy is more important. Creating a color by mixing varying amounts of other colors on this palette. This step is computer intensive since comparisons with as many as eight neighboring pixels is required to perform this process properly.