The 1/2.9" sensor size is a specification that describes the physical dimensions of the image chip in a camera. This fractional notation format is historical and does not directly indicate the actual diagonal in inches. In this specific case, the sensor's diagonal is approximately 6.2 millimeters. The physical size of the sensor affects the quality of the resulting photograph or video. A larger sensor is able to capture more light, which leads to better results in poor lighting conditions, for example, at dusk. This results in less so-called digital noise, which appears on the image as unwanted graininess. Sensors of this size are often used in webcams, security cameras, and some mobile phones, where they represent a compromise between price, device dimensions, and image quality.