Camera system incorporating a seamless lens-drive switching mechanism

A camera system incorporating a seamless lens-drive switching mechanism, comprising:

• a lens drive ring which moves a movable lens group forward and rearward in an optical axis direction by rotating about an axis of said lens drive ring;
• a manual operation ring which is manually rotated to rotate said lens drive ring;
• an electric motor for rotating said lens drive ring;
• a first one-way rotational transfer mechanism for transferring a rotation of said manual operation ring to said lens drive ring when said manual operation ring is manually rotated in a manual rotation operation, and for preventing a rotation of said lens drive ring from being transferred to said manual operation ring when said lens drive ring is rotated by said electric motor in an electric rotation operation;
• a second one-way rotational transfer mechanism for transferring a rotation of said electric motor to said lens drive ring when said electric motor rotates in the electric rotation operation, for being brought into the second neutral state after rotation of said electric motor is reversely rotated by a predetermined amount after said electric motor is stopped in the electric rotation operation, and for preventing a rotation of said lens drive ring from being transferred to said electric motor when said lens drive ring rotates in the manual rotation operation;
• a clutch device, incorporated in said second one-way rotational transfer mechanism, for transferring said rotation of said electric motor to said lens drive ring when said electric motor rotates in one of forward and reverse directions, and to bring said clutch device into a neutral state when said electric motor subsequently rotates in the other of said forward and reverse directions by a predetermined amount of rotation;
• and
• a controller which makes said electric motor stop rotating and subsequently makes said electric motor rotate in a reverse direction by a predetermined amount of rotation to thereby disengage said electric motor and said second one-way rotational transfer mechanism from each other after said electric motor is rotated so as to rotate said lens drive ring, and which controls said lens drive ring to transfer rotation of said manual operation ring in the manual rotation operation and which controls said lens drive ring to transfer rotation of said electric motor in the electric rotation operation;
• wherein upon said manual operation ring being manually rotated, said lens drive ring is rotated via said first one-way rotational transfer mechanism.

A photographic lens which is detachably attachable to a camera body, said photographic lens having a seamless lens-drive switching mechanism and comprising:

• a lens drive ring which moves a movable lens group forward and rearward in an optical axis direction by rotating about an axis of said lens drive ring;
• a manual operation ring which is manually rotated to rotate said lens drive ring;
• a motor rotation transfer mechanism for rotating said lens drive ring in accordance with a rotational force transferred from said camera body when said photographic lens is detachably attached to said camera body;
• a first one-way rotational transfer mechanism which prevents said manual operation ring and said lens drive ring from being connected with each other in a first neutral state, which connects said manual operation ring with said lens drive ring so that a rotation of said manual operation ring is transferred to said lens drive ring when said manual operation ring rotates in either direction from said first neutral state, and which maintains said first neutral state even when said lens drive ring is rotated by said motor rotation transfer mechanism in said first neutral state;
• a second one-way rotational transfer mechanism which prevents said motor rotation transfer mechanism and said lens drive ring from being connected with each other in a second neutral state, which connects said motor rotation transfer mechanism with said lens drive ring so that a rotation of said motor rotation transfer mechanism is transferred to said lens drive ring when said motor rotation transfer mechanism rotates in either direction from said second neutral state, and which maintains said second neutral state even when said lens drive ring is rotated by said manual operation ring in said second neutral state;
• a memory which stores a value of a predetermined amount of rotation amount necessary for bringing said second one-way rotational transfer mechanism into said second neutral state when said motor rotation transfer mechanism is rotated in an opposite rotational direction upon said rotation of said motor rotation transfer mechanism is stopped after said motor rotation transfer mechanism rotates in one of forward and reverse directions so as to drive said lens drive ring;
• and
• a data output device for outputting said predetermined amount of rotation to said camera body.

A camera body to which a photographic lens is detachably attachable, said camera body comprising:

• a data input device for inputting data from said photographic lens when said photographic lens is detachably attached to said camera body;
• an electric motor;
• a motor rotation transfer mechanism for transferring rotation of said electric motor to said photographic lens when said photographic lens is detachably attached to said camera body;
• a memory which stores data of the amount of backlash of said electric motor and said motor rotation transfer mechanism when a lens rotation transfer mechanism provided in said photographic lens is driven via said electric motor and said motor rotation transfer mechanism;
• and
• a controller which inputs lens data via said input device and drives said electric motor in accordance with said lens data;
• wherein in the case where said photographic lens, which is detachably attached to said camera body, includes a lens drive ring which moves a movable lens group forward and rearward in an optical axis direction by rotating about an axis of said lens drive ring, a manual operation ring which is manually rotated to rotate said lens drive ring;
• said lens rotation transfer mechanism for rotating said lens drive ring in accordance with a rotational force transferred from said camera body when said photographic lens is detachably attached to said camera body, a first one-way rotational transfer mechanism which prevents said manual operation ring and said lens drive ring from being connected with each other in a first neutral state, which connects said manual operation ring with said lens drive ring so that a rotation of said manual operation ring is transferred to said lens drive ring when said manual operation ring rotates in either direction from said first neutral state, and which maintains said first neutral state even when said lens drive ring is rotated by said motor rotation transfer mechanism in said first neutral state, a second one-way rotational transfer mechanism which prevents said motor rotation transfer mechanism and said lens drive ring from being connected with each other in a second neutral state, which connects said motor rotation transfer mechanism with said lens drive ring so that a rotation of said motor rotation transfer mechanism is transferred to said lens drive ring when said motor rotation transfer mechanism rotates in either direction from said second neutral state, and which maintains said second neutral state even when said lens drive ring is rotated by said manual operation ring in said second neutral state, a lens memory which stores a value of a predetermined amount of rotation amount necessary for bringing said second one-way rotational transfer mechanism into said second neutral state when said lens rotation transfer mechanism is rotated in an opposite rotational direction upon said rotation of said lens rotation transfer mechanism being stopped after said lens rotation transfer mechanism rotates in one of forward and reverse directions so as to drive said lens drive ring, and a data output device for outputting said predetermined amount of rotation to said camera body, said controller calculates a driving amount of said electric motor necessary for bringing said second one-way rotational transfer mechanism into said second neutral state based on said backlash amount a value of a predetermined rotational amount which is input via said data input device.

A photographic lens which is detachably attachable to a camera body, said photographic lens having a seamless lens-drive switching mechanism and comprising:

• a lens drive ring which moves a movable lens group forward and rearward in an optical axis direction by rotating about an axis of said lens drive ring;
• a manual operation ring which is manually rotated to rotate said lens drive ring;
• an electric motor for rotating said lens drive ring;
• a first one-way rotational transfer mechanism which prevents said manual operation ring and said lens drive ring from being connected with each other in a first neutral state in an electric rotation operation, which connects said manual operation ring with said lens drive ring so that a rotation of said manual operation ring is transferred to said lens drive ring when said manual operation ring rotates in either direction from said first neutral state in a manual rotation operation, and which maintains said first neutral state even when said lens drive ring is rotated by said electric motor in said first neutral state in the electric rotation operation;
• a second one-way rotational transfer mechanism which prevents said electric motor and said lens drive ring from being connected with each other in a second neutral state in manual rotation operation, which connects said electric motor with said lens drive ring so that a rotation of said electric motor is transferred to said lens drive ring when said electric motor rotates in either direction from said second neutral state in the electric rotation operation, which is brought into the second neutral state after said electric motor is reversely rotated by a predetermined amount after rotation of said electric motor is stopped in the electric rotation operation, and which maintains said second neutral state even when said lens drive ring is rotated by said manual operation ring in said second neutral state in the manual rotation operation;
• and
• a controller which makes said electric motor stop rotating and subsequently makes said electric motor rotate in a reverse direction by a predetermined amount of rotation to bring said second one-way rotational transfer mechanism into said second neutral state after said electric motor rotates so as to rotate said lens drive ring, and which controls said lens drive ring to transfer rotation of said manual operation ring in the manual rotation operation and which controls said lens drive ring to transfer rotation of said electric motor in the electric rotation operation;
• wherein upon said manual operation ring being manually rotated, said lens drive ring is rotated via said first one-way rotational transfer mechanism.