Camera system

An interchangeable lens camera system comprising:

• an interchangeable lens comprising:
• a photographic optical system,
• a lens mount to mount the interchangeable lens,
• a lens side communication terminal to communicate to and from the interchangeable lens,
• a first storage circuit to store first lens data representing an optical property of said photographic optical system of said interchangeable lens in an unrewritable manner,
• a second storage circuit to store second lens data used to adjust a variation of the optical property of said photographic optical system of said interchangeable lens without a supply of external power, and
• a lens side communication device to transmit said first and second lens data stored in said first and second storage circuit, respectively, through said lens side communication terminal;
• and
• a camera body comprising:
• a body mount engageable with said lens mount to mount said interchangeable lens on said camera body,
• a sensor to receive light from a field through said photographic optical system and to generate an output corresponding to the light received, when said interchangeable lens is mounted on the camera body by said body mount,
• a processing circuit to process the output generated from said sensor and to output a condition signal, based on the processed output, indicating a condition of a subject image formed by said photographic optical system,
• a body side communication terminal connected to said lens side communication terminal to communicate with said lens side communication terminal, when said interchangeable lens is mounted on the camera body by said body mount,
• a body side communication device to communicate with said lens side communication device, through said body side communication terminal and said lens side communication terminal, to receive said first and second lens data transmitted from said lens side communication device, and
• a correction device to receive said condition signal from said processing circuit and said first and second lens data from said body side communication device, and to correct said condition signal based on said first and second lens data.

An interchangeable lens assembly, detachably mountable to a camera body which comprises an intended focal plane, a body mount, a body communication terminal, a focus detection device to detect a focus adjustment condition through a photographic optical system in a lens mounted to said body mount to calculate a defocus amount of an image plane of a photographic optical system to the intended focal plane, and a correction circuit to correct said defocus amount, comprising:

• a photographic lens optical system forming a subject image on the intended focal plane in said camera body;
• a storage circuit to store lens data without a supply of external power, said lens data including data representing an optical property intrinsic to the photographic optical system of said interchangeable lens assembly,. said lens data being electrically erasable or rewritable;
• a lens communication terminal connected to said body communication terminal when said lens is mounted on said camera body;
• and
• a lens communication device to transmit the lens data stored in said storage circuit to the correction circuit of said camera body through said lens communication terminal and said body communication terminal when the lens is mounted on said camera body, said correction circuit of the camera body adjusting said defocus amount based on the lens data transmitted thereto.

A focus detection system comprising a camera body and an interchangeable lens assembly,

• said camera body comprising:
• an intended focal plane on which a subject image is focused,
• a body mount to mount a lens,
• a body communication terminal connectable with another communication terminal,
• a focus detection device to detect a focus adjustment condition through a photographic optical system in a lens mounted to said body mount to calculate a defocus amount of an image plane of a photographic optical system to an intended focal plane, and
• a correction circuit to correct said defocus amount;
• and
• said interchangeable lens assembly comprising:
• a photographic lens optical system for forming a subject image on the intended focal plane in said camera body,
• a storage circuit to store lens data without a supply of external power, said lens data including data representing an optical property intrinsic to the photographic lens optical system of said interchangeable lens, which is used to correct said defocus amount, said lens data being electrically erasable or rewritable,
• a lens communication terminal connectable with said body communication terminal when the lens is mounted on said camera body, and
• a lens communication device to transmit the lens data stored in said storage circuit to the correction circuit of said camera body through said lens communication terminal and said body communication terminal when the lens is mounted on said camera body, said correction circuit correcting said defocus amount based on the lens data transmitted thereto.

An interchangeable lens assembly, detachably mountable to a camera body which comprises an intended focal plane, a body mount, a body communication terminal and a correction circuit, comprising:

• a photographic lens optical system forming a subject image on the intended focal plane in said camera body;
• a storage circuit to store lens data without a supply of external power, said lens data including data representing an optical property intrinsic to the photographic optical system of said interchangeable lens, said lens data being electrically erasable or rewritable;
• a lens communication terminal connected to said body communication terminal when said lens is mounted on said camera body;
• and
• a lens communication device to transmit the lens data stored in said storage circuit to the correction circuit of said camera body through said lens communication terminal and said body communication terminal when the lens is mounted on said camera body,
• said correction circuit to correct a focus or photometry value of said subject image based on said lens data.

An interchangeable lens assembly, detachably mountable to a camera body which comprises an intended focal plane and a body mount, comprising:

• a photographic lens optical system forming a subject image on the intended focal plane in said camera body;
• a storage circuit to store lens data without a supply of external power, said lens data including data representing an optical property intrinsic to the photographic optical system of said interchangeable lens, said lens data being electrically erasable or rewritable;
• a device to determine the lens data in accordance with a characteristic of said photographic lens optical system measured when a lens is assembled;
• and
• a correction circuit of said camera body to correct a focus or photomerry value of said subject image based on said lens data.

A focus detection system comprising a camera body and an interchangeable lens assembly,

• said lens assembly comprising:
• a photographic lens optical system to form an object image, and
• an electric erasable and programmable read only memory to store lens data of an off-axis aberration property intrinsic to said photographic lens optical system of the interchangeable lens without a supply of external power,
• said camera body comprising:
• a focus detecting device to detect a defocus amount of said object image in an off-axis position, and
• a correcting circuit to correct said defocus amount based upon said lens data stored in said electric erasable and programmable read only memory.

An interchangeable lens camera system comprising:

• an interchangeable lens comprising:
• a photographic optical system,
• a lens mount to mount the interchangeable lens,
• a lens side communication terminal to communicate to and from the interchangeable lens,
• a storage circuit to store lens data representing a manufacturing error or a time-lapsed variation error of said photographic optical system of said interchangeable lens without a supply of external power, and
• a lens side communication device to transmit the lens data stored in said storage circuit through said lens side communication terminal;
• and
• a camera body comprising:
• a body mount engageable with said lens mount to mount said interchangeable lens on said camera body,
• a sensor to receive light from a field through said photographic optical system and to generate an output corresponding to the light received, when said interchangeable lens is mounted on the camera body by said body mount,
• a processing circuit to process the output generated from said sensor and to output a condition signal, based on the processed output, indicating a focus or photometry condition of a subject image formed by said photographic optical system,
• a body side communication terminal connected to said lens side communication terminal to communicate with said lens side communication terminal, when said interchangeable lens is mounted on the camera body by said body mount,
• a body side communication device to communicate with said lens side communication device, through said body side communication terminal and said lens side communication terminal, to receive said lens data transmitted from said lens side communication device, and
• a correction circuit to receive said condition signal from said processing circuit and said lens data from said body side communication device, and to correct said condition signal based on said lens data thereby to correct a focus or photometry value of said subject image.