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US 5,311,243 AGranted
Flash photographing system
AssigneeCanon Kabushiki Kaisha
InventorTatsuyuki Tokunaga
Life of this patent
Estimating the term…
Abstract
In a flash photographing system, measuring light is calculated by dividing a picture plane into a plurality of areas and adjusting a quantity of flash light on the basis of light measurement outputs obtained from the plurality of areas. The light measurement outputs are evaluated and weighted according to focusing states of the areas, and the weighting values are varied according to the kind of automatic focusing mode selected, so that a quantity of flash light can be controlled appositely to the automatic focusing mode selected.
Claims14
A flash photographing system for photographing with flash light emitted from a flash device, comprising:
- a) a light measuring circuit arranged to measure light obtained in each of different areas of a scene, said light measuring circuit being arranged to measure, in a flash photography mode, a reflected light obtained from an object to be photographed as a result of flashing by the flash device;
- b) a light quantity control circuit arranged to adjust a quantity of flash light emitted from the flash device on the basis of light measurement outputs of said light measuring circuit obtained by measuring light in each of the different areas;
- c) mode selection means for selecting a first focusing mode or a second focusing mode different from said first focusing mode;
- d) a condition setting circuit operably responsive to said mode selection means and arranged to vary an adjustment condition for adjustment of the quantity of flash light by said light quantity control circuit according to the selected focusing mode;
- and
- e) a focus detecting circuit arranged to detect a focusing state of each of the different areas and to form focusing state signals which correspond respectively to the different areas;
- wherein said condition setting circuit is arranged to set the adjustment condition at a predetermined condition according to a focusing state of each of the different areas of a scene when the selected focusing mode is said first focusing mode and to set the adjustment condition at a condition different from the predetermined condition when the focusing mode is said second focusing mode.
4 more elements
A flash photographing system for photographing with flash light emitted from a flash device, comprising:
- a) a light measuring circuit arranged to measure light obtained in each of different areas of a scene, said light measuring circuit being arranged to measure, in a flash photography mode, a reflected light obtained from an object to be photographed as a result of flashing by the flash device;
- b) an evaluating condition setting circuit arranged to set an evaluating condition for a light measurement output obtained from each of the different areas;
- c) mode selection means selecting a first focusing mode or a second focusing mode different from said first focusing mode;
- d) a light quantity control circuit arranged to adjust a quantity of flash light emitted from the flash device on the basis of each of the light measurement outputs, said light quantity control circuit being arranged to adjust the quantity of flash light by taking into consideration the evaluating condition determined by said evaluating condition setting circuit for each of the light measurement outputs;
- e) a condition varying circuit arranged to vary the evaluating condition according to the focusing mode;
- and
- f) a focus detecting circuit arranged to detect a focusing state of each of the different areas and to form focusing state signals which correspond respectively to the different areas,
- wherein said condition varying circuit is arranged to set a predetermined evaluating condition according to a focusing state of each of the different areas of a scene when the selected focusing mode is said first focusing mode, and to set an evaluating condition different from the predetermined evaluating condition when the selected focusing mode is said second focusing mode.
5 more elements
A flash photographing system for photographing with flash light emitted from a flash device, comprising:
- a) a light measuring circuit arranged to measure light obtained in each of different areas of a scene, said light measuring circuit being arranged to measure, in a flash photography mode, a reflected light obtained from an object to be photographed as a result of flashing by the flash device;
- b) an integrating circuit arranged to individually integrate light measurement outputs obtained from the different areas and to produce integration signals which correspond respectively to the light measurement outputs;
- c) a stopping circuit arranged to bring emission of flash light by the flash device to a stop when even any one of the integration signals reaches a predetermined value;
- d) a focus detecting circuit arranged to detect a focusing state of each of the different areas and to form focusing state signals which correspond respectively to the different areas;
- and
- e) an adjustment circuit arranged to individually control integrating actions on the light measurement outputs obtained from the different areas on the basis of the focusing states of the different areas detected by said focus detecting circuit when a focusing mode of a camera is a first mode, and to control the integrating actions irrespectively of the focusing states of the different areas when the focusing mode is a second mode different from the first mode.
3 more elements
A flash photographing system for photographing with flash light emitted from a flash device, comprising:
- a) a light measuring circuit arranged to measure light obtained in each of different areas of a scene, said light measuring circuit being arranged to measure, in a flash photography mode, a reflected light obtained from an object to be photographed as a result of flashing by the flash device;
- b) a light quantity control circuit arranged to adjust a quantity of flash light emitted from the flash device on the basis of light measurement outputs of said light measuring circuit obtained by measuring light in each of the different areas;
- c) a condition setting circuit arranged to vary an adjustment condition for adjustment of the quantity of flash light by said light quantity control circuit according to a focusing mode of a camera;
- and
- d) a focus detecting circuit arranged to detect a focusing state of each of the different areas and to form focusing state signals which correspond respectively to the different areas;
- wherein said condition setting circuit is arranged to set different adjustment conditions for a light measurement output obtained from an in-focus area among said different areas and for light measurement outputs obtained from other areas when the focusing mode is a first mode and to set the same adjustment condition for light measurement outputs of all areas when the focusing mode is a second mode different from the first mode.
3 more elements
A flash photographing system for photographing with flash light emitted from a flash device, comprising:
- a) a light measuring circuit arranged to measure light obtained in each of different areas of a scene, said light measuring circuit being arranged to measure, in a flash photography mode, a reflected light obtained from an object to be photographed as a result of flashing by the flash device;
- b) an evaluating condition setting circuit arranged to set an evaluating condition for a light measurement output obtained from each of the different areas;
- c) mode selection means for selecting a first focusing mode or a second focusing mode different from said first focusing mode;
- d) a light quantity control circuit arranged to adjust a quantity of flash light emitted from the flash device on the basis of each of the light measurement outputs, said light quantity control circuit being arranged to adjust the quantity of flash light by taking into consideration the evaluating condition determined by said evaluating condition setting circuit for each of the light measurement outputs;
- e) a condition varying circuit arranged to vary the evaluating condition according to the focusing mode;
- f) a focus detecting circuit arranged to detect a focusing state of each of the different areas and to form focusing state signals which correspond respectively to the different areas;
- and
- g) a focus adjustment circuit which selects one of said different areas and adjusts the focus on the basis of a focus signal detected by the focus detecting circuit in said selected area, wherein said condition varying circuit sets the evaluating condition for the outputs in said selected area and the non-selected areas to a predetermined condition when the focusing mode is a first focusing mode and sets the evaluating condition to a condition different from the condition under the first focusing mode when the focusing mode is a second focusing mode.
5 more elements
Dependencies are inferred from the claim text.