Tips And Tricks
Understand the Differences Between CMOS and CCD Sensors.
All digital cameras have an image sensor that is used to capture information and create a photograph. There are two primary types of image sensors - CMOS and CCD - and each has their own advantages.
How Does an Image Sensor Work?
The image sensor is to think of it as the equivalent of a piece of film. When the shutter button on a digital camera is depressed, light enters the camera.The image is exposed onto the sensor in the same way that it would be exposed onto a piece of film in a 35mm film camera.
Digital camera sensors consist of a number of pixels which collect photons that are converted into an electrical charge by the photodiode.
DSLR cameras and point and shoot cameras primarily use two types of image sensors: CMOS & CCD.
What is a CCD Image Sensor?CCD (Charge Coupled Device) sensors convert pixel measurements sequentially using circuitry surrounding the sensor. CCDs use a single amplifier for all of the pixels.
There are some distinct advantages to a CCD sensor:
CMOS sensors are more commonly used in DSLRs as they are faster and cheaper.
The CMOS sensor also has its advantages:
Color Filter Array Sensors & Foveon Sensors
A Color Filter Array Sensors A color filter array is fitted to the top of the sensor to capture red, green, and blue components of light falling on the sensor. Therefore, each pixel is only able to measure one color. The other two colors are estimated by the sensor based on the surrounding pixels.
While this can affect image quality slightly, it is hardly noticeable on today's high-resolution cameras.
Most current DSLRs use this technology.
Human eyes are sensitive to the three primary colors of red, green, and blue and other colors are worked out by a combination of the primary colors. In film photography, the different primary colors expose the corresponding chemical layer of film.
Foveon sensors have three sensor layers, which each measure one of the primary colors. An image is produced by combining these three layers to produce a mosaic of square tiles. This is still fairly new technology, and it is currently only being used by Sigma.