Optical image stabilisation (OIS): how a camera cancels hand shake

Optical image stabilisation (OIS) is a mechanism in the camera that physically shifts the lens or sensor in the opposite direction to your hand shake so photos and videos come out sharp.

OIS cancels shake like a smart wrist

In plain words

Imagine carrying a full glass of water with a slightly shaky hand. If your wrist gently counters every movement, the water does not spill. OIS is the camera's "smart wrist": the gyroscope senses the phone wobble, and tiny motors instantly shift the lens the other way.

How it works

The phone's gyroscope measures the slightest hand movements.
The controller calculates how far to shift the lens or sensor.
Miniature actuators (magnetic coils) move the optics in the opposite direction.
The image on the sensor stays still.
The camera can "gather light" for longer without blur - which helps at night.

Tiny motors shift the lens against the shake

Where you'll see it

OIS is found in the main cameras of most mid-range and flagship smartphones and in flagship telephoto lenses. Specs say "OIS" or "optical image stabilisation". Some flagships use sensor-shift stabilisation.

Does it matter when buying

Yes, for night photos, video on the move and zoom shots. I recommend choosing a phone with OIS at least on the main camera. Without it, you will get more blurry shots at night, and walking video will shake even with electronic stabilisation.

Myths

Myth: OIS and EIS are the same. Reality: OIS moves the optics physically; EIS crops and shifts the frame in software.
Myth: With OIS you can film while running with no shake. Reality: OIS cancels small movements; for running you also need strong electronic stabilisation or a gimbal.

FAQ

How can I tell if a phone has OIS?

Check the specs, or open the camera and gently shake the phone - with OIS the image "floats" smoothly.

Can motorbike vibrations damage OIS?

Strong, constant vibrations can damage the mechanism, so mounts with a damper are worthwhile.

What is sensor-shift?

A type of OIS in which the sensor moves instead of the lens.