US 4,792,820 AGranted

Camera with automatic focus and exposure control means

AssigneeMinolta Camera Kabushiki Kaisha

InventorsToshio Norita, Nobuyuki Taniguchi, Tokuji Ishida, Toshihiko Karasaki, Masataka Hamada

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Abstract

A camera with an AF and AE control structure including a one-shot AF mode and a continuous AF mode, in which the operability and exposure control are improved. The camera includes a unit for detecting a focusing condition of an objective lens, defined by the relationship between a position of an object to be photographed against the lens and a focus point of the lens; a unit for focusing the lens in accordance with the detected focusing condition so that the lens is moved to the in-focus position, a first light measurement unit for measuring light at a spot area corresponding to a region of the object to be detected at the detecting unit, a second light measurement means for measuring averaged light at another area broader than the first area, and a unit for controlling exposure amount. The exposure control unit determines the exposure amount on the basis of the spot metering data in a one-shot AF mode, or the averaged light measuring data which is defined as a data at a time, at least, when the lens is adjacent to the in-focus position, in a continuous AF mode.

Claims42

Dependent claims

A camera with an automatic focus and exposure (AF and AE) control means, comprising:

means for detecting a focusing condition of an objective lens attached to the camera to produce a focusing signal indicative of the detected focusing condition;
means for selecting either a first operation mode or a second operation mode;
means, operatively connected to said detecting means and said selecting means, for focusing the objective lens in accordance with the focusing signal to produce an in-focus signal when the in-focus condition of the objective lens is established, the operation of the focusing means being interrupted after the in-focus condition has once been established when the first operation mode is selected, and the operation of the focusing means being repeated in accordance with the focusing signal even if an out-of-focus condition is detected again after the in-focus condition has once been established when the second operation mode is selected;
first light measurement means for measuring light from a first measuring area corresponding to a focus detection area to produce a first light measuring signal indicative of an intensity of light measured, the light from the focus detection are being received by the detecting means for detecting the focusing condition of the objective lens;
second light measurement means for measuring light coming from a second measuring area larger than the first measuring area to produce a second light measurng signal indicative of an intensity of light measured;
and
exposure control means, operatively connected to said first and second light measurement means, said selecting means and said focusing means, for controlling exposure amount on the basis of the first light measuring signal produced when the in-focus signal is produced in the condition in which the first operating mode is selected, and for controlling exposure amount on the basis of the second light measuring signal independently of the in-focus signal in the condition in which the second operation mode is selected.

4 more elements

A camera with an automatic focus and exposure (AF and AE) control means, comprising:

means for detecting a focusing condition of an objective lens attached to the camera to produce a focusing signal indicative of the detected focusing condition;
means, operatively connected to said detecting means, for focusing the objective lens in accordance with the focusing signal to produce an in-focus signal when the in-focus condition of the objective lens is established, the operation of the focusing means being repeated in accordance with the focusing signal even if an out-of-focus condition is established again after the in-focus condition has once been detected;
first light measurement means for measuring light coming from a first measuring area corresponding to a focus detection area to produce a first light measuring signal indicative of an intensity of light measured, the light from the focus detecting area being received by the detecting means for detecting the focusing condition of the objective lens;
second light measurement means for measuring light coming from a second measuring area larger than the first measuring area to produce a second light maasuring signal indicative of an intensity of light measured;
and
exposure control means, operatively connected to said first and second light measurement means and said focusing means, for controlling exposure amount on the basis of the first light measuring signal when the in-focus signal is produced at a time of starting the exposure control operation, and for controlling exposure amount on the basis of the second light measuring signal when the in-focus signal is not produced at a time of starting the exposure control operation.

3 more elements

A camera with an automatic focus and expsoure (AF and AE) control means, comprising:

means for detecting a direction of defocus of an objective lens and amount of defocus thereof with respect to a predetermined focal plane;
means, operatively connected to said detecting means, for focusing the objective lens in accordance with the detected direction of defocus and the detected amount of defocus to stop the focusing of the objective lens and to produce an in-focus signal when the detected amount of defocus becomes smaller than a predetermined first amount;
first light measurement means for measuring light coming from a first measuring area corresponding to a focus detection area to produce a first light measuring signal indicative of an intensity of light measured, the light from the focus detection area being received by the detecting means for detecting the direction of defocus and the amount of defocus of the objective lens;
second light measurement means for measuring light coming from a second measuring area larger than the first measuring area to produce a second light measuring signal indicative of an intensity of light measured;
and
exposure control means, operatively connected to said first and second light measurement means, and said focusing means, for controlling exposure amount on the basis of the first light measuring signal when the in-focus signal is produced at a time of starting the exposure control operation, and for controlling exposure amount on the basis of the second light measuring signal when the in-focus signal is not produced at a time of starting the exposure control operation.

3 more elements

A camera with an automatic focus and exposure (AF and AE) control means, comprising:

means for detecting a focusing condition of an objective lens attached to the camera to produce a focusing signal indicative of the detected focusing condition;
means, operatively connected to said detecting means, for focusing the objective lens in accordance with the focusing signal to produce an in-focus signal when the in-focus condition of the objecitve lens is established, the operation of the focusing means being repeated in accordance with the focusing signal even if an out-of-focus condition is detected again after the in-focus condition has once been detected;
light measurement means for repeatedly measuring light coming from a measuring area corresponding to a focus detection area to repeatedly produce a light measuring signal indicative of an intensity of light measured, the light from which is received by the detecting means for detecting the focusing condition of the objective lens;
means for updating said light measuring signal while said in-focus signal is produced and for storing a last light measuring signal when said in-focus signal is not produced;
and
means, operatively connected to said update and storing means, for controlling exposure amount on the basis of said stored light measuring signal.

3 more elements

Dependencies are inferred from the claim text.