A Guide for Understanding the Camera Sensor

Two types of sensors are used in digital cameras: CCD and CMOS. CMOS stands for Complementary Metal Oxide Semiconductor, and CCD stands for Charge-Coupled Device. CMOS sensors are less expensive than CCD and also require less power (because the CCD requires more circuits), so the latest digital cameras are based on CMOS sensors (still, the majority of cameras use CCD). It is impossible to say which one is better because both of them have advantages and disadvantages. But, if the camera software is designed to eliminate the leaks of the sensor type, a good camera may come out (classic example is the use of noise reduction system on CMOS based cameras).

Principle of CCD:
In digital imaging, when the light waves that entered the camera are focused on the sensor which converts light into an electrical charge, the image is formed.
It is simple: the more light that hits the photodiode, the greater the charge. But how does this process separate the colors? The light entering the camera is the normal white light containing all the wavelengths, so inside the mechanism these wavelengths will be separated by filters based on the basic RGB (red-green-blue). The information is read row by row and pixel by pixel, therefore, the necessary processing time is a bit longer, but it is very accurate.

Principle of CMOS:
A CMOS sensor, instead of converting the light wave into an electrical charge on a different chip, it converts the photons into electrons by processing the data at this point (and not on another chip). By using amplifiers, these sensors are faster than CCDs. However, the fact that not all converters and amplifiers work at different efficiencies, may cause noise.
While most CMOS use the same RGB filtration system, there is also a new revolutionary technology called Foveon (Sigma started using it but in the future more manufacturers will introduce models based on this technology), which uses the properties of silicon itself to filter out the colors of light spectrum.
Camera Sensor

Tags: camera sensors, CMOS sensor, CCD sensor, camera sensor, Foveron, CMOS, CCD



I started photography as a hobby in 2005, during college. My passion slowly became a more important part of my life since 2008. Because of using a combination of my photographic knowledge, with those of internet marketing, I like to call myself a "photomarketer".

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