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Comment by vFunct

2 days ago

I actually used to design image sensor chips. The dynamic range is due to the electron well size. Each pixel has a diode that stores typically between 10,000-100,000 electrons in them. When the shutter is open, each photon that arrives pushes out an electron across the diode. When the shutter closes, sensors count how many electrons remain. This is how they calculate how much light each pixel received.

The well size itself is usually a function of the pixel size. A larger pixel means a larger diode that can store more electrons, and hence a larger range of light that can be measured - dynamic range.

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vFunct

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mediaman  2 days ago

So there's a tradeoff between image resolution and dynamic range, for a given sensor size?

  • vFunct  2 days ago

    Sorta. If you subdivide an area into more pixels you get lower dynamic range for each pixel, but you can average across multiple pixels to gain back the some of the dynamic range.