what a pixel is and what how a camera sensor is usually designed. A Pixel is something that can reproduce or capture light, in the camera sensor, it’s capturing light. A pixel is comprised of 4 sub-pixels, usually this is Red, Green and Blue, which is where RGB comes from, all colours can be digitally reproduced from different combinations of these three colours, and they are arranged in a 2×2 grid of RGGB, because the human eye is very sensitive to Green and we model camera sensors on our physiology.
there are other ways to create a brighter image, the most common one is to just have a bigger sensor and therefore each pixel is larger, but in a smartphone, space is already at a premium, so just shoving a bigger sensor in a phone isn’t all that practical, so what companies started doing was oversampling. This meant that a company would effectively quarter it is resolution, but would double the light sensitivity, it would take the data from 4 pixels next to each other and create a larger “pixel” but the problem with this is that the sensor isn’t designed to plop for pixels together, so colours suffer, and there is only so much that software can do. Introducing, the quad bayer filter.
What is a quad bayer filter? Well, in a simple way, it is a way to design a sensor with the resolution benefits of a higher megapixel sensor (higher detail) but with the benefit of larger pixels (more light sensitivity). These are sensors that have a certain amount of megapixels, but they are arranged in a way to make the best of oversampling, which means you’ll usually see the phone take a picture at a quarter the resolution of what the camera is marketed at, and you weren’t lied to, but marketing is always a bit tricky.
