reflex camera Camera that allows the user to view and focus through the lens. A plane mirror and prism reflect the scene through the lens on to a ground glass screen. When the photographer presses the shutter on a single-lens reflex (SLR) camera, the mirror flips back and light reaches the film. A twin-lens reflex (TLR) camera has two sets of lenses, one for viewfinding, the other for passing light directly onto the film. See also photography

re·flex cam·er·a • n. a camera with a ground glass focusing screen on which the image is formed by a combination of lens and mirror, enabling the scene to be correctly composed and focused.