Auto ISO is not inherently bad—it’s a tool. Used well, it can be very effective, especially when your priority is getting the shot. In many situations, a noisy image is better than no image at all.

Best practice is to first understand the exposure triangle: aperture, shutter speed, and ISO. Learning exposure manually helps you recognize when the camera’s automatic choice is appropriate and when to override it.

A practical approach is:

• Use Auto ISO when light is changing or when speed matters.
• Set ISO manually when image quality is the top priority and lighting is consistent.
• Learn your camera’s noise limits so you know what ISO range still gives acceptable results for your needs.
• Consider the light you’re in ahead of time (daylight, indoors, night) and choose settings accordingly.
• If needed, use a faster lens to keep ISO lower.

Many photographers regularly use modes like aperture priority with Auto ISO because it’s fast and effective. The key is not to avoid Auto ISO, but to understand what it’s doing and when it aligns with your creative goal.