Understanding Image Sensor and File Types

A sensor is a silicon semiconductor meant for acquiring photons and converting them into electrons. You could compare this process to millions of tiny buckets collecting rain water. The more photons that are collected the brighter the captured area. Once they are full, they overflow. What flows over gets lost. This is often referred to as “blooming” or “clipped highlights”. When this occurs all detail in these highlight areas is lost.

The sensor records images in black and white. There is a filter in front of the sensor known as the ‘Bayer Filter’.  This filter assigns a color value of either red, green or blue to each pixel. There are twice as many green elements as red or blue to mimic the human eye’s greater resolving power with green light. These elements are referred to as sensor elements, pixel sensors, or simply pixels; sample values, after interpolation, become image pixels.

The digital camera sensor is made up of millions of these pixels. Resolution (pixel count) is only a part of what that contributes to picture quality. How the image is processed for color and tone can be technically more important. A simple doubling of megapixels, even if all else remained the same, is very subtle. The factors that matter such as color and sharpening algorithms will be far more significant.