Position detecting apparatus and optical apparatus

An optical apparatus comprising:

• a position detecting apparatus;
• and
• an optical element configured to move in an optical axis direction as a rotating member rotates,
• wherein the position detector includes:
• a rotating member rotatable and having a first cam and a second cam;
• a first detector having a first moving unit moved by the first cam as the rotating member rotates, the first detector being configured to output a first signal corresponding to a position of the first moving unit;
• a second detector having a second moving unit moved by the second cam as the rotating member rotates, the second detector being configured to output a second signal corresponding to a position of the second moving unit;
• and
• a rotational position acquirer configured to acquirer a rotational position of the rotating member using the first signal and the second signal,
• wherein the first cam moves the first moving unit in a first rotational range of the rotating member and a second rotational range following the first rotational range,
• wherein the second cam moves the second moving unit in the second rotational range of the rotating member and a third rotational range following the second rotational range, and
• wherein the rotational position acquirer acquires the rotational position using the first signal in the first rotational range and in part on a first rotational range side in the second rotational range, and acquires the rotational position using the second signal in the third rotational range and in part on a third rotational range side in the second rotational range.