How Your Camera Turns Light Into a Photo

Every photo you take begins with a grid of millions of microscopic light buckets.

So how does a camera turn something as untouchable as light into a digital image you can keep forever?

Light travels as tiny particles called photons. Your sensor is covered in millions of microscopic wells called photosites, one for every pixel. When photons strike a photosite, they knock electrons loose. That is the photoelectric effect, the discovery that won Einstein his Nobel Prize. Brighter light sends more photons, so more electrons pile up inside the well. When the shutter closes, the camera measures the charge collected in each well, and a converter translates that tiny voltage into a number. Millions of numbers, side by side, become your picture.

Here is the strange part. A raw sensor is completely colorblind. Each well only counts how much light landed inside it, never what color it was.

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