How digital cameras use digital technology

Once a picture is stored in numeric form, you can do all kinds of things with it. Plug your digital camera into your computer, and you can download the images you've taken and load them into programs like PhotoShop to edit them or jazz them up. Or you can upload them onto websites, email them to friends, and so on. This is possible because your photographs are stored in digital format and all kinds of other digital gadgets—everything from MP3-playing iPods to cellphones and computers to photo printers—use digital technology too. Digital is a kind of language that all electronic gadgets "speak" today. Photo: Digital cameras are much more convenient than film cameras. You can instantly see how the picture will look from the LCD screen on the back. If your picture doesn't turn out okay, you can simply delete it and try again. You can't do that with a film camera. Digital cameras mean photographers can be more creative and experimental. If you open up a digital photograph in a paint (image editing) program, you can change it in all kinds of ways. A program like this works by adjusting the numbers that represent each pixel of the image.

So, if you click on a control that makes the image 20 percent brighter, the program goes through all the numbers for each pixel in turn and increases them by 20 percent. If you mirror an image (flip it horizontally), the program reverses the sequence of the numbers it stores so they run in the opposite direction. What you see on the screen is the image changing as you edit or manipulate it. But what you don't see is the paint program changing all the numbers in the background. Some of these image-editing techniques are built into more sophisticated digital cameras. You might have a camera that has an optical zoom and a digital zoom. An optical zoom means that the lens moves in and out to make the incoming image bigger or smaller when it hits the CCD. A digital zoom means that the microchip inside the camera blows up the incoming image without actually moving the lens. So, just like moving closer to a TV set, the image degrades in quality. In short, optical zooms make images bigger and just as clear, but digital zooms make images bigger and more blurred.