What is a bridge plate?
A bridge plate, also called a dovetail clamp, is a type of mount used to attach a camera to a dovetail plate. It is a plate that attaches to the bottom of a camera or other piece of equipment and has a dovetail channel running along one or more edges. The dovetail channel allows for quick and easy attachment and detachment of the equipment to a tripod or other support system. Furthermore, in conjunction with the dovetail plate, the bridge plate facilitates easy repositioning of the camera along its optical axis, enabling quick balancing on the tripod head.
A dovetail bridge plate typically attaches to the camera or other equipment using standard 3/8″ or 1/4″ screws, and can be locked in place on the dovetail plate using a locking mechanism, such as a lever or knob. Most dovetails are equipped with safety catches on one or both ends, to prevent accidental removal of an unlocked bridge plate.