What are the differences between gain and ISO in photography, and how do they affect the quality of an image?

In Photography, gain and ISO both control the brightness of an image, but they work differently. Gain adjusts the signal strength of the sensor, while ISO amplifies the signal after it's been captured.

Using a higher gain can introduce more noise to the image, affecting its quality, while increasing ISO can also lead to noise but may result in a brighter image. Finding the right balance between gain and ISO is important to maintain image quality.