ISO controls how sensitive your camera sensor is to light. Lower ISO numbers like 100 or 200 are less sensitive — ideal for sunny days and sharp images. Higher ISO numbers like 1600 or 3200 make your sensor more sensitive — helpful in low light, but can add grain or “noise.”

Together with shutter speed and aperture, ISO is part of the exposure triangle that determines brightness.

What ISO Affects

  • Exposure: Higher ISO brightens the photo
  • Noise: Higher ISO can reduce detail or add grain
  • Shutter speed options: A higher ISO allows faster shutter speeds in low light

When to Change ISO

  • Keep ISO low (100–400) in bright conditions
  • Raise ISO (800–3200 or more) in dim settings like indoors or at night
  • Use ISO to balance exposure when you need a faster shutter or narrower aperture

Tips

  • Start with Auto ISO, then experiment with manual settings
  • Don't be afraid of high ISO — today’s cameras handle it better than ever
  • Use exposure compensation if ISO alone doesn't give you the result you want

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