ECONOMIC GROWTH: AN INTRODUCTION

A camera seal assembly has a first retainer having an opening. The first retainer defines an axis extending through the opening. A second retainer is disposed in fixed relation to the first retainer. The second retainer faces the first retainer in spaced relation along the axis. A barrel extends through the opening. The barrel has a cylindrical barrel wall. A collar has a side wall facing the barrel wall. The barrel is movable relative to the collar. A stack of alternating lesser and greater rings is disposed between the first and second retainers and between the barrel wall and side wall. The lesser rings are movable relative to the greater rings in directions radial to the axis. The stack has a centered state, in which each lesser ring more closely adjoins the barrel wall than the side wall and each greater ring more closely adjoins the side wall than the barrel wall.