A between-the-lens shutter, also known as a leaf shutter, is a type of shutter with overlapping blades positioned within the lens assembly, usually close to the diaphragm. When triggered, the blades open and close to control the exposure time precisely, allowing light to reach the film or sensor. Leaf shutters are valued for their quiet operation, high flash synchronization speeds, and even exposure across the frame, making them common in medium- and large-format cameras, studio photography, and situations requiring flash use.