A bellows shutter is a traditional type of camera shutter that consists of a pair of expandable bellows which, when closed together, form a hemispherical enclosure around the lens. This design was used in early large-format and field cameras to control the duration of light exposure on the film or plate. Bellows shutters offer precise, mechanical control over exposure, and are an important part of the history of classic photography techniques, giving insight into how photographers managed light before modern electronic shutters.