Why does the Xiaomi 15 Ultra make abnormal noise when shaking?

The Xiaomi 15 Ultra is equipped with OIS (Optical Image Stabilization) technology, which helps reduce motion blur and improve image clarity by compensating for small hand movements. To allow the OIS system to function properly, a certain amount of space is intentionally left within the camera module for the OIS motor to move freely.
As a result, when the device is shaken, you will hear a slight rattling or shifting sound. This is not a defect but rather a normal characteristic of OIS-equipped high-end camera modules. Many flagship smartphones with advanced optical stabilization exhibit similar behavior.
Please rest assured that this sound does not indicate any hardware issues and does not affect the phone’s functionality or camera performance. You can continue to use your Xiaomi 15 Ultra with confidence, knowing that this is an expected feature of its sophisticated camera system.