A TLR, or twin-lens reflex camera, is a type of camera that uses two lenses of the same focal length. The upper lens serves as the viewfinder lens with a mirror reflex system, allowing the photographer to compose and focus the image, while the lower lens is the taking lens that exposes the film or sensor.
TLR cameras are popular in medium-format photography and studio work because they provide precise framing and focus without the parallax issues found in other camera types. Understanding TLR operation allows photographers to take advantage of its unique design for sharp, high-quality images with consistent composition.