The greater the sensitivity in photography, the greater the "noise"? How to understand?

The terms "noise" and "noise" are the same. "Noise" is just a broader term that also applies to digital imaging, and many professional articles also call it this way.

The "noise" of digital photos is actually similar to the "noise" of a radio. We know that when the signal received by the radio is very weak, the radio will amplify the signal at a high level through automatic gain control, and the noise will also be amplified. Amplified, so the broadcast "noise" heard is very loud. Similarly, when a digital camera uses a high sensitivity setting, the light signal received by the camera during exposure is reduced, and the signal needs to be highly amplified during the camera's internal data processing, which can also easily produce "noise".

It is easy to understand why the high ISO of digital SLR has less "noise". For the same pixel, the single pixel area of ??digital SLR is large, and under the same weak light, more light signals are collected, so The amplification of the signal does not have to be very large, so the "noise" is low.