Photo-optical devices are instruments that utilize light to capture, analyze, or manipulate images. Common examples include cameras, microscopes, and telescopes. These devices rely on lenses and sensors to focus light and produce clear images, making them essential in fields like photography, science, and astronomy. These devices can be categorized into two main types: passive and active. Passive devices, like cameras, rely on natural light, while active devices, such as laser rangefinders, emit their own light to gather information. Both types play crucial roles in various applications, from medical diagnostics to environmental monitoring.