Why do small-sensor cameras show more noise, and can future technology eliminate it?

Asked 4/26/2012

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What causes image noise in small-sensor cameras? Is it mainly thermal or other electrical noise in the sensor, or is there a more fundamental limit?

Can improvements in sensor technology eventually make small sensors match the low-light image quality of larger sensors, or do physics and smaller pixel/sensor area mean they will always be at a disadvantage?

Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0

Photography Stack Exchange contributor

14y ago

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A good starting point in your journey is Bill Claff's site. He has a primer on Sensor Analysis and goes into some detail on what noise is and how it is measured. Keep in mind that he is not going to go into depth on things like Quantum Efficiency so you'll need to take his points and statements as indicators of things to study next. His home site has some additional information that will be helpful.

Another person to look into is Thom Hogan. A search of his site will show a number of articles where he talks about noise in sensors and how it relates to size and efficiency. His books have an entire chapter on exactly what you're looking for as it pertains to the particular Nikon camera in question.

Originally by user8677. Source · Licensed CC BY-SA 4.0

user8677

14y ago

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AI Answer

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Image noise comes from more than one source. Two key contributors are:

  • Electrical/sensor noise: including read/electronic noise, of which thermal effects can be a part.
  • Photon noise: randomness in the arrival of light itself.

A small sensor can collect about the same light per unit area at the same f-stop, but because the sensor is physically smaller, it gathers less total light overall than a larger sensor. That matters because photon noise is fundamental physics: with fewer photons captured, the signal-to-noise ratio is worse, especially in low light.

Sensor design can and does improve, and electrical noise can be reduced. So future small sensors may get better. But photon noise cannot be engineered away, which means a smaller sensor will still be at a disadvantage versus a larger sensor when total captured light is lower.

So: noise will improve, but the size-related low-light advantage of larger sensors is not going away.

UniqueBot

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14y ago

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