Camera system

• US 5,111,231 A
• Filed: 07/23/1990
• Issued: 05/05/1992
• Est. Priority Date: 07/27/1989
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tokunaga, Tatsuyuki
• Primary Examiner(s): PERKEY, WILLIAM B
• Application Number:
  US07/557,172
• Time in Patent Office: 652 Days
• Field of Search: 354/402, 354/403, 354/416, 354/417, 354/413, 354/429, 354/432, 354/431
• US Class Current: 396/123
• CPC Class Codes: G03B 15/05 Combinations of cameras with electronic flash apparatus; Electronic flash units
• CPC Class Codes: G03B 7/09979 Multi-zone light measuring

Abstract

A camera system of the kind adjusting flash light quantity comprises a focus detecting circuit which detects the focused state of each of a plurality of areas arranged within an image field, and a light measuring circuit which measures the luminance of each of the areas of the image field respectively. In the camera system, the light measurement outputs obtained from these areas are individually weighted according to the focused states of the areas detected, and the quantity of flash light is adjusted on the basis of the weighted outputs of the light measuring circuit.

Claims

1. A flash photographing system for photographing with flash light of a flash device, comprising:

a) a light measuring circuit which individually measures light of a plurality of areas of an image field, said light measuring circuit being arranged to measure reflected light coming from a photographed object as a result of flashing in case of flash photography;

b) a focus detecting circuit which performs a focus detecting action on each of different areas of said image field;

c) a setting circuit which sets the flash light quantity condition on the basis of a focused state of each of said areas detected by said focus detecting circuit; and

d) a light quantity control circuit including an integrating circuit arranged to perform an integrating action on the light measurement output of said light measuring circuit for each of said areas and a stopping circuit arranged to stop the flash light from being emitted when an output of said integrating circuit reaches a predetermined value, said integrating action being performed in accordance with each flash light adjusting condition set by said setting circuit.

2. A system according to claim 1, wherein said setting circuit is arranged to set said condition differently for a light measurement output of said light measuring circuit obtained for an area which, among said plurality of areas, indicates an in-focus state from conditions set for light measurement outputs obtained for other areas.

3. A system according to claim 1, further comprising a lens driving circuit arranged to drive a lens to focus the lens on a photographed object located in one of said plurality of areas on the basis of the result of focus detection obtained for said area, and wherein said setting circuit is arranged to set said condition for a light measurement output of said light measuring circuit for said area differently from light measurement outputs for other areas.

4. A flash photographing system according to claim 1, wherein said integrating circuit integrates the light measurement outputs of each of the areas independently and the stopping circuit stops emission of the flash light when any one of outputs of the integration reaches a predetermined value.

5. A flash photographing system for photographing with flash light of a flash device, comprising:

a) a light measuring circuit which individually measures light of a plurality of areas of an image field, said light measuring circuit being arranged to measure reflected light coming from a photographed object as a result of flashing in case of flash photography;

b) a focus detecting circuit which performs a focus detecting action on each of different areas of said image field;

c) an evaluating condition setting circuit arranged to determine an evaluating condition for a light measurement output obtained for each of said areas on the basis of a focused state of each of said areas detected by said focus detecting circuit; and

d) a light quantity control circuit including an integrating circuit arranged to perform an integrating action on the light measurement output of said light measuring circuit for each of said areas and a stopping circuit arranged to stop the flash light from being emitted when an output of said integrating circuit reaches a predetermined value, said integrating action being performed in accordance with each evaluating condition determined by said setting circuit.

6. A system according to claim 5, wherein said setting circuit is arranged to set said condition differently for a light measurement output of said light measuring circuit obtained for an area which, among said plurality of areas, indicates an in-focus state from conditions set for light measurement outputs obtained for other areas.

7. A system according to claim 5, further comprising a lens driving circuit arranged to drive a lens to focus the lens on a photographed object located in one of said plurality of areas on the basis of the result of focus detection obtained for said area, and wherein said setting circuit is arranged to set said condition for a light measurement output of said light measuring circuit for said area differently from light measurement outputs for other areas.

8. A system according to claim 5, wherein said setting circuit is arranged to attach weight to each of said light measurement outputs.

9. A flash photographing system according to claim 5, wherein said integrating circuit integrates the light measurement outputs of each of the areas independently and the stopping circuit stops emission of the flash light when any one of outputs of the integration reaches a predetermined value.

10. A flash photographing system for photographing with flash light of a flash device, comprising:

a) a light measuring circuit which individually measures light of a plurality of areas of an image field, said light measuring circuit being arranged to measure reflected light coming from a photographed object as a result of flashing in case of flash photography;

b) a focus detecting circuit which performs a focus detecting action on each of different areas of said image field;

c) an evaluating condition setting circuit arranged to determine an evaluating condition for a light measurement output obtained for each of said areas on the basis of a focused state of each of said areas detected by said focus detecting circuit; and

d) a light quantity control circuit including an integrating circuit arranged to perform an integrating action on the light measurement output of said light measuring circuit for each of said areas and a stopping circuit arranged to stop the flash light from being emitted when the sum of the outputs of said integrating circuit reaches a predetermined value, said integrating action being performed in accordance with each evaluating condition determined by said setting circuit.

11. A camera system comprising:

a) a light measuring circuit arranged to individually measure light of a plurality of areas of an image field;

b) a focus detecting circuit which performs a focus detecting action on each of different areas of said image field;

c) a lens driving circuit arranged to adjust focus by driving a lens on the basis of the result of the focus detecting action of said focus detecting circuit;

d) holding means arranged to hold said lens in a focus-adjusted position after said lens is driven to the focus-adjusted position by said lens driving circuit and to inhibit any lens driving action thereafter;

e) an evaluation circuit which evaluates the light measurement outputs of each of said areas measured by said light measuring circuit on the basis of the focus states of each of said areas detected by said focus detecting circuit after the lens is held at a focus-adjusted position by said holding means but immediately before a release operation; and

f) an exposure control circuit arranged to perform exposure control on the basis of said evaluated light measurement output.

12. A system according to claim 11, wherein said exposure control circuit is arranged to control the quantity of flash light to be emitted.

13. A camera system, comprising:

a) a light measuring circuit arranged to individually measure light of a plurality of areas of an image field;

b) a focus detecting circuit which performs a focus detecting action on each of different areas of said image field;

c) a computing circuit arranged to predict by computation the position of a photographed object to be obtained within an image field after the lapse of a predetermined period of time on the basis of a focused state of each of said areas detected in the past by said focus detecting circuit;

d) an evaluation circuit arranged to evaluate an output of said light measuring circuit obtained for an area corresponding to a position predicted by said computing circuit in a manner different from a manner in which outputs of said light measuring circuit for areas other than said area are evaluated; and

e) an exposure control circuit arranged to perform exposure control on the basis of said evaluated light measurement output, said exposure control circuit being arranged to control the quantity of flash light to be emitted.

14. A camera system comprising:

a) a light measuring circuit arranged to individually measure light of a plurality of areas of and image field;

b) a focus detecting circuit which performs a focus detecting action on each of different areas of said image field;

c) a lens driving circuit arranged to select the result of focus detection detected from one of said areas by said focus detecting circuit and to drive a lens for focus adjustment on the basis of said result of focus detection;

d) holding means arranged to hold said lens in a focus-adjusted position after said lens is driven to the focus-adjusted position by said lens driving circuit and to inhibit any lens driving action thereafter;

e) a selection circuit which selects a light measuring area on the basis of the focus states of each of said areas detected by said focus detecting circuit after the lens is held at a focus-adjusted position by said holding means but immediately before a release operation; and

f) an exposure control circuit which performs exposure control on the basis of a light measurement output of said light measuring circuit obtained from said area selected by said selection circuit.

15. A system according to claim 14, wherein said exposure control circuit is arranged to control the quantity of flash light to be emitted.

16. A camera system, comprising:

a) a light measuring circuit arranged to individually measure light of a plurality of areas of and image field;

b) a focus detecting circuit which performs a focus detecting action on each of different areas of said image field;

c) a computing circuit arranged to predict by computation the position of a photographed object to be obtained within an image field after the lapse of a predetermined period of time on the basis of a focused state of each of said areas detected in the past by said focus detecting circuit; and

d) an exposure control circuit arranged to perform exposure control on the basis of an output of said light measuring circuit obtained for an area corresponding to a position predicted by said computing circuit, said exposure control circuit being arranged to control the quantity of flash light to be emitted.

17. A flash photographing system for photographing with flash light of a flash device, comprising:

a) a light measuring circuit which individually measures light of a plurality of areas of an image field, said light measuring circuit being arranged to measure reflected light coming from a photographed object as a result of flashing in case of flash photography;

b) a focus detecting circuit which performs a focus detecting action on each of different areas of said image field;

c) a setting circuit which sets the flash light quantity condition on the basis of a focused state of each of said areas detected by said focus detecting circuit; and

d) a light quantity control circuit including an integrating circuit arranged to perform an integrating action on the light measurement output of said light measuring circuit for each of said areas and a stopping circuit arranged to stop the flash light from being emitted when the sum of outputs of said integrating circuit reaches a predetermined value, said integrating action being performed in accordance with each flash light quantity condition determined by said setting circuit.