A hidden camera or spy camera is a still or video camera used to record people without their knowledge. The term “hidden camera” is commonly used in TV shows, sometimes when subjects are unaware that they are being recorded, and usually lacking their knowledge and consent. The term “spy camera” is generally used when the subject would object to being recorded if they were aware of the camera's existence. In contrast, "security cameras" refer to cameras that are visible and/or accompanied by a warning notice of their presence.