Which ISO setting minimizes digital noise and yields the cleanest image?

• A. ISO 400
• B. ISO 100
• C. ISO 800
• D. ISO 1600

Answer: (B)

Lower ISO means less amplification of the sensor signal, so you get the cleanest image with the least digital noise. ISO 100 is typically the base setting where the sensor’s own signal is boosted the least, preserving more detail and tonal range, especially in shadows and highlights. This is why it yields the cleanest results when you have enough light, or when you can use a longer shutter or wider aperture to maintain correct exposure.

If lighting is poor, you’d need more exposure time, a wider aperture, or you’d have to increase ISO to get a proper brightness. Raising ISO increases the sensor gain, which also amplifies noise and can reduce dynamic range and color fidelity. So, the best approach for minimal noise is to shoot at ISO 100 whenever exposure allows.