How are surveillance cameras described in terms of their optics?

• A. By their color
• B. By their lens diameter 1/3, 1/2, 2/3
• C. By their frame rate
• D. By their power supply voltage

Answer: (B)

Surveillance cameras are described by the size of their image sensor, usually given in fractions of an inch like 1/3", 1/2", or 2/3". These numbers refer to the sensor’s diagonal size, not the actual lens diameter, and they matter for optics because they influence how much of the scene the camera can capture and how well it performs in varying light. A larger sensor collects more light and generally provides a wider field of view with the same lens, plus better low-light performance. So describing a camera’s optics by these sensor sizes is the standard way to convey optical characteristics. Other specs like color, frame rate, or power supply voltage relate to different aspects of performance, not the optical description.