Lens device and method

A lens device, comprising

• a lens;
• a lens barrel that contains the lens;
• an operation ring that is rotatably held by the lens barrel;
• a movement device that moves the lens corresponding to rotation of the operation ring;
• a motor having a rotatable shaft connected to the movement device, wherein the motor can generate electric power through rotation of the rotatable shaft;
• a transfer device that rotatably connects the operation ring to the rotatable shaft of the motor;
• and
• a load circuit that consumes the generated electric power generated by the motor.

A method for focussing a lens, the method comprising the steps of:

• holding a lens in a lens barrel;
• movably connecting operation member parts to the lens barrel;
• moving the lens in accordance with movement of the operation member parts;
• generating, with electric generation means, electric power from the movement of the operation member parts;
• and
• consuming, with electric consuming means, the generated electric power generated in the generating step.

A lens device operable in a manual focus mode and an automatic focus mode, the lens device comprising:

• a lens supported by a lens barrel;
• an operation ring rotatably coupled to the lens barrel, wherein the lens barrel and the lens are moved by rotation of the operation ring;
• and
• a lens drive device coupled to the operation ring, the lens drive device including:
• a motor,
• a motor drive circuit operatively engagable with the motor,
• a variable resistor operatively engagable with the motor, and
• a selection switch selectively connecting the motor drive circuit to the motor in the automatic focus mode and the variable resistor to the motor in the manual focus mode.