In photography terms, what does ISO control?

ISO, in terms of photography, controls the sensitivity of your camera's sensor to light. Here's a step-by-step explanation:

1. ISO is a setting on your camera that will either increase or decrease the sensitivity of the sensor to light.

2. When you increase the ISO number, you increase the sensor's sensitivity to light. This means that the sensor requires less light to create a well-exposed photograph.

3. Conversely, when you decrease the ISO number, you decrease the sensor's sensitivity to light. This means that the sensor requires more light to create a well-exposed photograph.

4. However, increasing the ISO also increases the amount of noise or grain in the photograph. This is why photographers often try to use the lowest ISO possible for the amount of light available.

5. In summary, ISO controls the balance between the sensor's sensitivity to light and the amount of noise in the photograph.