Camera system and lens barrel

A camera system, comprising:

• a first barrel;
• a second barrel that is capable of relative rotation around an optical axis with respect to the first barrel;
• a drive source;
• a focusing lens;
• a drive portion that is driven by the drive source, and that drives the focusing lens in an optical axis direction;
• a rotational operation member that is a member operated for driving the focusing lens in the optical axis direction, and that can move in the optical axis direction to a first position at which the rotational operation member covers the second barrel and to a second position at which the rotational operation member causes the second barrel to be exposed to outside, and which is configured to be capable of rotation around the optical axis at the first position and the second position, respectively;
• and
• engagement means that, when the rotational operation member is at the second position, causes the second barrel and the rotational operation member to engage with each other and rotates the second barrel accompanying rotation of the rotational operation member, and when the rotational operation member is at the first position, disengages the second barrel and the rotational operation member from each other;
• wherein, when the rotational operation member is at the first position, the drive portion drives the focusing lens in accordance with rotation of the rotational operation member, and when the rotational operation member is at the second position, the drive portion drives the focusing lens in accordance with rotation of the second barrel that is engaged with the rotational operation member.