Mount apparatus and accessories

A mounting apparatus on which an accessory including a first mount is mountable, the mounting apparatus comprising:

• a second mount that is capable of coupling to the first mount of the accessory;
• a plurality of terminals disposed along a circumferential direction of the second mount and used for electrical connection with corresponding terminals provided on the accessory;
• a terminal holder that holds the plurality of terminals;
• and
• a plurality of mount claws for engaging with a plurality of claws provided in the accessory,
• wherein the terminal holder has a first stage, a second stage, and a boundary portion between the first stage and the second stage, where the first stage and the second stages are at different positions in a direction parallel to a center-axis direction of the second mount and the plurality of terminals is disposed over the first stage and the second stage,
• wherein the plurality of terminals includes a first terminal used to detect mounting of the accessory and a second terminal used to supply communication control power to the accessory,
• wherein the second stage is projecting toward the accessory further than the first stage in a state where the accessory is mounted on the mounting apparatus,
• wherein, among plural terminals disposed on the first stage of the terminal holder, the first terminal is disposed to be closest to the boundary portion, and
• wherein, among plural terminals disposed on the second stage of the terminal holder, the second terminal is disposed to be farthest from the boundary portion.