Optical Image Stabilisation (OIS) is a mechanical system built into camera modules that reduces blur caused by camera movement. Unlike software-based stabilisation, which crops and enlarges the image, OIS physically shifts lens elements or the entire sensor to compensate for shake in real time.
How it works: Tiny motors detect motion using gyroscopes, then move glass elements within the lens or shift the sensor itself to counteract that movement. This happens continuously while you hold down the shutter button, keeping the captured scene steady on the sensor.
Why it matters for mobile users:
- Sharper photos in low light without boosting ISO (which adds grain)
- Smoother video recording, especially when walking or filming handheld
- Longer effective shutter speeds, useful for creative effects
- Better results with telephoto lenses, where shake is magnified
Common misconceptions: OIS does not replace good technique. It reduces shake, not eliminates it entirely. Very fast movements or panning may still result in blur. It also drains battery faster than non-stabilised cameras.
What to look for: Not all phones include OIS, particularly on ultra-wide or telephoto cameras. Check specs carefully if you shoot frequently in dim conditions or record video often. Flagship and mid-range devices typically offer it on the main camera; budget phones rarely do.
If video stability matters to you, OIS is more effective than digital stabilisation alone, though many modern phones combine both systems.