When shooting handheld video in very low light conditions, what specific benefit does sensor-shift optical image stabilization provide beyond general camera shake reduction?

In very low light conditions when shooting handheld video, sensor-shift optical image stabilization provides the specific benefit of allowing significantly longer shutter speeds without introducing noticeable camera shake blur, thereby reducing the need to increase the ISO sensitivity. Sensor-shift optical image stabilization works by physically moving the camera's image sensor in real-time to counteract detected camera movements. Gyroscopic sensors within the camera precisely measure the degree and direction of any shake, and then electromagnets shift the sensor to keep the projected image stationary on its surface during the video frame's exposure. In low light, capturing enough light is critical. One common way to gather more light is by extending the shutter speed, which is the duration the camera's sensor is exposed to light. However, a longer shutter speed dramatically increases the risk of motion blur from even slight handheld camera movement, making the video appear blurry and unusable. The alternative to a longer shutter speed is to increase the ISO, which is the camera sensor's sensitivity to light. While higher ISO settings brighten the image, they concurrently introduce more image noise—undesirable graininess or speckles—and can reduce the dynamic range, making the video look less detailed and muddy. Sensor-shift optical image stabilization mitigates this dilemma. By stabilizing the image on the sensor itself, it effectively allows the camera to keep its shutter open for a longer duration—for example, a quarter-second or even a half-second for individual frames within the video—without the light from the scene 'smearing' across the sensor due to camera shake. This extended exposure time allows the sensor to collect substantially more light for each video frame. The crucial benefit is that this increased light collection means the videographer can maintain a lower ISO setting, resulting in significantly cleaner video footage with less image noise and better preservation of detail and color, compared to the noisy, often unusable footage that would result from trying to capture enough light solely by increasing ISO or from blurred footage due to handheld shake at slow shutter speeds without stabilization.