Abstract: A diaphragm control apparatus incorporated in a camera body, to which an interchangeable lens equipped with a diaphragm apparatus is detachably attached, the diaphragm apparatus including a diaphragm operatively-associated rod for driving an adjustable diaphragm to open and shut the adjustable diaphragm, and the diaphragm control apparatus including a slide member that is driven to move the diaphragm operatively-associated rod, the diaphragm control apparatus includes a diaphragm drive mechanism including a stepping motor and a lead screw which is driven to rotate by the stepping motor, wherein the slide member is moved by rotation of the lead screw, a position detector for detecting a position of the slide member, and a controller for adjusting an excitation phase of the stepping motor based on a stop position of the slide member detected by the position detector.

Abstract: An electromagnetic actuator is provided, including a bobbin made of a non-magnetic material including a hollow cylindrical portion and disk flanges; a coil formed between the disk flanges; a power supply which supplies a current to the coil; a movable member pivoted on the hollow cylindrical portion; and a stationary member made of a permanent magnet and fixed to a disk flange. The movable member is a magnetic material and includes a shaft portion and a rotating portion. The rotating portion is fixed to the shaft portion, lies on the disk flange, and extends in a radial direction of the shaft portion. When the power supply supplies the current to the coil in a predetermined direction, the rotating portion is magnetized to a predetermined polarity and rotates. The stationary member includes a stopper for stopping rotation of the movable member at a predetermined rotational position.

Abstract: A diaphragm control apparatus incorporated in a camera body, to which an interchangeable lens equipped with a diaphragm apparatus is detachably attached, the diaphragm apparatus including a diaphragm operatively-associated rod for driving an adjustable diaphragm to open and shut the adjustable diaphragm, and the diaphragm control apparatus including a slide member that is driven to move the diaphragm operatively-associated rod, the diaphragm control apparatus includes a diaphragm drive mechanism including a stepping motor and a lead screw which is driven to rotate by the stepping motor, wherein the slide member is moved by rotation of the lead screw, a position detector for detecting a position of the slide member, and a controller for adjusting an excitation phase of the stepping motor based on a stop position of the slide member detected by the position detector.

Abstract: An electromagnetic actuator is provided, including a bobbin made of a non-magnetic material including a hollow cylindrical portion and disk flanges; a coil formed between the disk flanges; a power supply which supplies a current to the coil; a movable member pivoted on the hollow cylindrical portion; and a stationary member made of a permanent magnet and fixed to a disk flange. The movable member is a magnetic material and includes a shaft portion and a rotating portion. The rotating portion is fixed to the shaft portion, lies on the disk flange, and extends in a radial direction of the shaft portion. When the power supply supplies the current to the coil in a predetermined direction, the rotating portion is magnetized to a predetermined polarity and rotates. The stationary member includes a stopper for stopping rotation of the movable member at a predetermined rotational position.