OIS (Optical Image Stabilization) working principle and main types

Optical Image Stabilization (OIS) is a technology that compensates for camera shake in real time by moving physical optical elements such as lenses or image sensors, effectively reducing image blur and improving image quality.

The core of an OIS system lies in real-time physical compensation via hardware. Its workflow typically involves three stages: First, motion sensors such as gyroscopes frequently detect the direction and magnitude of camera shake; then, a microprocessor (MCU) quickly calculates the amount and direction of compensation needed to counteract the shake; finally, an actuator (such as a voice coil motor, VCM) is driven to move the lens group or image sensor for reverse displacement compensation, thus stabilizing the optical path before light reaches the imaging element. Based on the different compensation elements, it is mainly divided into two types:

Lens-Moving OIS: This is the most mainstream technology, achieving compensation by driving a portion of the lens group within the lens to float. This technology was pioneered by traditional camera manufacturers such as Canon and Nikon and is widely used in smartphone cameras.

Sensor-Moving OIS: This compensates for shake by moving the image sensor (CMOS/CCD). This technology evolved alongside digital cameras and is also being used in some mobile devices.

The main value of OIS technology lies in significantly improving the success rate and image quality of handheld shooting. Its advantages are reflected in several aspects:

Improved Low-Light Shooting Capabilities: OIS allows the camera to use a slower

safe shutter speed (typically 2-4 stops slower), meaning that in low-light environments, exposure time can be extended to capture more light, thus avoiding the significant noise introduced by increasing ISO sensitivity, resulting in brighter and cleaner night scene photos.

Enhanced Telephoto-End Stability: When shooting at a telephoto distance, even slight shake is amplified, causing blur. OIS effectively compensates for this shake, making it an indispensable feature in telephoto photography.

Improved Video Shooting Experience: OIS provides more stable raw footage for video recording, reducing high-frequency shake and providing a better foundation for subsequent

electronic image stabilization processing, ultimately resulting in smoother and more fluid video.

Preserving Image Quality: Unlike electronic image stabilization (EIS), OIS compensates physically, eliminating the need for cropping or pixel interpolation, thus preserving resolution and field of view.

Comparison with Electronic Image Stabilization (EIS)

OIS is often discussed alongside EIS, but their principles and effects differ significantly. Modern devices often combine the two to form a hybrid stabilization solution.

Principle: Hardware physical compensation, stabilizing the optical path by moving optical components.

Advantages: No image cropping, lossless image quality; significantly effective in low-light and telephoto scenes.

Disadvantages: Requires additional hardware modules, increasing cost, device size, and power consumption; compensation range has physical limits.

Principle: Software algorithm compensation, predicting motion using gyroscope data, cropping image edges, and digitally stabilizing.

Advantages: Low cost, no dedicated hardware required; strong suppression of large-scale, low-frequency shaking (such as in walking shots).

Disadvantages: Crops the image, resulting in a reduced field of view (typically 10%-15%); may introduce image distortion such as the "rolling shutter effect"; primarily suitable for video, with limited benefit for still photos.