Shading device and lens barrel

A shading device employed in a lens barrel having at least a first lens group and a second lens group which move relative to each other along an optical axis with at least one of the first lens group and the second lens group allowed to rotate around the optical axis, comprising:

• a first shading member having one end thereof secured to the first lens group, a second shading member having one end thereof secured to the second lens group and at least one middle shading member provided between the first shading member and the second shading member, wherein:
• the first shading member, the second shading member and the middle shading member are each formed as a tube adopting a substantially circular-conical shape so as to allow the shading device to achieve a telescopic function and are set to overlap each other along the optical axis so that vertices of the circular cones face a same direction;
• and
• areas over which internal circumferential surfaces on smaller-diameter sides of the shading members overlap external circumferential surfaces on larger-diameter sides of adjacent shading members function as retaining portions which prevent disengagement of the middle shading member.

A shading device employed in a lens barrel having at least a first lens group and a second lens group which move relative to each other along an optical axis with at least one of the first lens group and the second lens group allowed to rotate around the optical axis, comprising;

• a light leakage preventing member with bellows provided between the first lens group and the second lens group, wherein:
• one end of the light leakage preventing member is secured to the first lens group set further toward a subject along the optical axis and another end of the light leakage preventing member is allowed to come into contact with the second lens group;
• a sliding member is provided at the other end of the light leakage preventing member to reduce friction between the other end and the second lens group;
• and
• a contact surface where the second lens group comes in contact with the other end of the light leakage preventing member includes a groove through which an adjustment of an air pressure in an interior space formed by the first lens group, the second lens group and the light leakage preventing member and an air pressure in an exterior space outside the interior space is achieved when a distance between the first lens group and the second lens group increases/decreases.