Digital Camera Computer Technology 3200 By: Brittany O’Brien
A Filmless Camera • Instead of film, a digital camera uses a sensor that converts light into electrical charges. • There are two different sensors used in different cameras, a charged couple device (CCD) or a complementary metal oxide semiconductor (CMOS). CCD CMOS
CCD • This image sensor transports the charge and reads it at one corner of the array. • Creates high-quality low-noise images • Consumes 100 times more power then CMOS sensors. • Higher quality pixels.
CMOS • Uses several transistors at each pixel to amplify and move the charge using more traditional wires • Signal is digital • More susceptible to noise • Consumes little power • Light sensitivity is lower
Resolution Resolution is the amount of detail a camera can capture when a picture is taken. The more pixels the camera has, the more detail it can capture and the larger the picture can be without becoming blurry.
Some typical resolutions are: • 256x256 - Found in very cheap cameras, 65000 total pixels • 640x480 – Low end on most “real” cameras • 1216x912 – “Megapixel” image size, 1 109 000 total pixels • 1600x1200 – High resolution, 2 million total pixels • 2240x1680 – 4 megapixel camera, the current standard • 4064x2704 – Found in a top of the line camera, 11. 1 megapixels.
Exposure A digital camera has to control the amount of light that reaches the center. Two components a digital camera uses to do this is the aperture and shutter speed.
Aperture: The size of the opening in the camera. It is automatic is most digital cameras. However, it can be adjusted for more control over the final image. Shutter Speed: The amount of time that light can pass through the aperture. The light sensor resets automatically so the digital camera has a digital shutter.
Focus In addition to controlling the amount of light, the camera has to adjust the lenses to control how the light is focused on the sensor. Most digital cameras do this automatically.
Lenses Digital cameras one of four types of lenses: Fixed-focus, fixed zoom lenses: This type of lens comes on a disposable camera. They are very limited, but inexpensive and great for snapshots.
Optical-zoom lenses with automatic focus: This lens has “wide” and “telephoto” options and automatic focus. These lenses are very similar to a lens you would find on a video camera. Digital zoom lenses: With this lens the cameras takes pixels from the center of the image sensor and averages the pixels to make a full-size image. Replaceable lens systems: Similar to a 35mm camera, some digital cameras can also use 35mm lenses.
Storing digital photos Many of today’s camera have fixed or removable flash memory. These flash memory devices Include SmartMedia cards, CompactFlash cards, and Memory sticks. CompactFlash
References http://electronics.howstuffworks.com/digital-camera6.htm http://images.google.ca/images?hl=en&q=digital+camera&gbv=2