The Truth about Digital ISO

The video explains that ISO is not the sensitivity of the camera sensor but an amplification setting applied to light after it is collected. It compares ISO to turning up the volume on a radio, where the signal remains unchanged but is amplified. A test is suggested to demonstrate that ISO does not affect noise in images. The video concludes that the amount of light received by the camera, controlled by aperture, shutter speed, and exposure, determines the signal-to-noise ratio, similar to how a better radio signal results in clearer sound.

What new insight or understanding did you gain from this video?