Camera apparatus having focus detecting sensitivity based on absolute focal length
AssigneeCanon Kabushiki Kaisha
InventorKoji Takahashi
Life of this patent
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Abstract
In a camera system including a camera unit and a lens unit which is detachably mounted on the camera unit, an automatic focusing apparatus comprises a focus signal forming circuit which forms a focus detection signal for indicating a focusing state of the lens unit, a focal length information outputting circuit which produces absolute focal length information on the absolute focal length of the lens unit, a transmission circuit which transmits the absolute focal length information to the camera unit, and a control circuit which controls the focus signal forming circuit on the basis of the absolute focal length information.
Claims27
A camera having a camera unit and a lens unit detachably mounted on said camera unit, comprising:
- a) focus signal forming means for forming a focus detection signal by detecting a focusing state;
- b) memory means for storing information corresponding to a plurality of areas defined by dividing a focal length variable range between a tele-end and a wide-end of said lens unit into a plurality of areas on the basis of an absolute focal length information of said lens unit;
- c) focal length information outputting means for outputting said absolute focal length information of said lens unit;
- d) transmission means for transmitting said absolute focal length information to said camera unit in a predetermined period of time;
- and
- e) control means for controlling said focus signal forming means on the basis of said area information on said absolute focal length information.
A camera system having a camera unit and a lens unit detachably mounted on said camera unit, comprising:
- a) output means for outputting a representative value of absolute focal length information of each of a plurality of divided areas set by dividing a variable range of focal length of said lens unit on the basis of said absolute focal length, said absolute focal length information being stored in memory means in said lens unit;
- b) focus detecting means for detecting a focusing state of said lens unit;
- c) control means for controlling an operation of said focus detecting means on the basis of an output of said output means;
- and
- d) transmitting means for transmitting said area information on said absolute focal length information to said camera in a predetermined period of time.
A camera system having a camera unit and a lens unit detachably mounted on said lens unit, comprising:
- a) focus detecting means for detecting a focusing state of said lens unit to produce a focus control signal for controlling the focusing state of said lens unit;
- b) driving means for controlling the focusing state of said lens unit on the basis of the focus control signal output from said focus detecting means;
- c) output means for outputting a plurality of area information formed by dividing a variable range of a focal length of said lens unit on the basis of an absolute focal length of said lens unit, said area information formed on the basis of said absolute focal length being stored in a memory in said lens unit;
- d) control means for controlling the sensitivity of said focus detecting means in accordance with said area information formed on the basis of said absolute focal length;
- and
- (e) communication means for communicating the focus control signal output from said focus detecting means and said area information formed on the basis of said absolute focal length between said lens unit and said camera unit, wherein said communication means is arranged to perform, in a predetermined period of time, data communication between microcomputers which are respectively disposed on the sides of said lens unit and said camera unit.
A lens unit detachably mounted on a camera body, comprising:
- (a) lens means movably provided for varying a focal length;
- (b) memory means for storing a plurality of regions set by dividing a variable range of focal length of said lens means on the basis of an actual and absolute focal length;
- (c) output means for outputting information of a region corresponding to a position of said lens means read out from said memory means;
- and
- (d) communication means for communicating said information of the region to said camera body according to an instruction from said camera body.
Dependencies are inferred from the claim text.