Exposure control apparatus of camera

• US 5,602,616 A
• Filed: 01/30/1995
• Issued: 02/11/1997
• Est. Priority Date: 04/15/1991
• Status: Expired due to Term

• Current Assignee: PENTAX RICOH IMAGING COMPANY, LTD.
• Original Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
• Inventors: Shishikura, Takenao, Sato, Osamu, Sensui, Takayuki, Hirai, Isamu, Yamamoto, Masato, Nakano, Satoshi, Takahashi, Akio, Kitazawa, Toshiyuki, Matsudo, Nobuhiko, Yamanaka, Toshimasa
• Primary Examiner(s): ADAMS JR, RUSSELL E
• Application Number:
  US08/380,314
• Time in Patent Office: 743 Days
• Field of Search: 354/441, 354/442, 354/443
• US Class Current: 396/238
• CPC Class Codes: G03B 7/097 for control of both exposure time and aperture

Abstract

A camera having a manually actuable switch for temporarily shifting the camera to an optimum exposure value so that exposure factors, based upon a manually set shutter speed and a manually set aperture value, are replaced by optimum exposure factors based upon a metered brightness of the object to be photographed when the camera is set to a non-program exposure mode. A clear button associated with the camera functions as a manually actuable switch for temporarily shifting an exposure mode of the camera to another exposure mode when the camera is set to a hyper-manual exposure mode. In the hyper-manual exposure mode, a photographer sets exposure factors by actuating a Tv electronic dial and an Av electronic dial. Actuation of the clear button when the camera is set to the hyper-manual exposure mode causes the set exposure factors to be replaced with optimum exposure factors that are automatically calculated in accordance with an object brightness Bv. Thus, operating the clear button (manually actuable switch for temporarily shifting to another exposure mode) results in the mode of the camera being changed from a mode in which exposure factors are manually set by a photographer (via the setting of a shutter speed and an aperture value) to a mode in which optimum exposure factors are set based upon a calculation performed by a processor of the camera.

Claims

1. An exposure control apparatus of a camera, comprising:

photometering means for metering a brightness of an object to be photographed;

means for manually setting a shutter speed;

means for manually setting an aperture value;

mode changing means for selecting an exposure mode from among a plurality of exposure modes, including a manual exposure mode in which a shutter speed and an aperture value are manually set by said manually setting shutter speed means and by said manually setting aperture value means, and an automatic exposure mode in which at least one of said shutter speed and said aperture value is automatically set in accordance with an other of said at least one of said shutter speed and said aperture value, and said object brightness;

exposure factor determining means for automatically determining at least one of said shutter speed and said diaphragm value, said exposure factor determining means being actuated when a presently selected mode is said automatic exposure mode; and

a manually actuable switch for replacing said manually set shutter speed and manually set aperture value with at least one automatically set shutter speed and aperture value when said manually actuable switch is actuated while the presently selected mode is said manual exposure mode.

2. The exposure control apparatus of claim 1, wherein said shutter speed and said aperture value determined by said exposure factor determining means in said automatic exposure mode are automatically set as values for adjustment by said manually setting shutter speed means and said manually setting aperture value means on shifting to said manual exposure mode.

3. The exposure control apparatus of claim 2, wherein said camera comprises:

a camera body; and

a photographing lens detachably attachable to said camera body, wherein said photometering means, said exposure factor determining means, and said manually actuable switch are provided in said camera body.

4. The exposure control apparatus of claim 3, wherein said manually setting shutter speed means and said manually setting aperture value means are provided in said camera body.

5. The exposure control apparatus of claim 3, wherein said manually setting shutter speed means is provided in said camera body, and said manually setting aperture value means is provided in said photographing lens.

6. The exposure control apparatus of claim 5, wherein said manually setting aperture value means provided in said photographing lens comprises a diaphragm ring movable between an auto-diaphragm position in which said aperture value is set on said camera body, and a manual diaphragm position in which said aperture value is set on said photographing lens.

7. The exposure control apparatus of claim 2, wherein said shutter speed and said aperture value are manually varied in accordance with said manually setting shutter speed means and said manually setting diaphragm value means, respectively, when said mode manually actuable switch is disabled while the presently selected mode is said manual exposure mode.

8. The exposure control apparatus of claim 2, wherein said manually actuable switch is actuated by depressing and holding a button.

9. The exposure control apparatus of claim 2, wherein said shutter speed and said diaphragm value are varied in accordance with said manually setting shutter speed means and said manually setting aperture value means, respectively, upon a release of said mode modifying switch.

10. The exposure control apparatus of claim 1, wherein said automatic exposure mode comprises:

a program exposure mode in which said exposure factor determining means determines said shutter speed and said aperture value in accordance with said object brightness;

a diaphragm value priority mode in which said exposure factor determining means determines said shutter speed in accordance with said object brightness detected by said photometering means and said aperture value set by said manually setting aperture value means; and

a shutter speed priority mode in which said exposure factor determining means determines said aperture value in accordance with said object brightness detected by said photometering means and said shutter speed set by said manually setting shutter speed means.

11. The exposure control apparatus of claim 10, wherein said manual exposure mode is shifted to one of said program exposure mode, said diaphragm value priority mode and said shutter speed priority mode when said manually actuable switch is actuated while the presently selected mode is said manual exposure mode.

12. The exposure control apparatus of claim 11, further comprising an indicator for indicating said exposure mode selected by said mode changing means, said selected exposure mode, said shutter speed and said aperture value.

13. The exposure control apparatus of claim 12, wherein exposure factors, including said shutter speed and said aperture value, are varied between values having one of a first APEX value accuracy and a second APEX value accuracy.

14. The exposure control apparatus of claim 13, wherein said second APEX value accuracy is higher than said first APEX value accuracy.

15. The exposure control apparatus of claim 14, wherein said exposure factors are varied by said manually setting shutter speed means and said manually setting aperture value means between values having said first APEX value accuracy.

16. The exposure control apparatus of claim 15, wherein said exposure factor determining means includes means for calculating an optimum value for at least one of said exposure factors in accordance with said object brightness detected by said photometering means, said optimum value being rounded to a value having one of said first APEX value accuracy or said second APEX value accuracy.

17. The exposure control apparatus of claim 16, wherein an optimum shutter speed and an optimum aperture value are set with said first APEX value accuracy when said manually actuable switch is actuated while the presently selected mode is said manual exposure mode.

18. The exposure control apparatus of claim 16, wherein an optimum shutter speed and an optimum aperture value are set with said second APEX value accuracy when said manually actuable switch is actuated while the presently selected mode is said manual exposure mode.

19. The exposure control apparatus of claim 16, wherein an optimum shutter speed is set with said first APEX value accuracy when said manually actuable switch is actuated and said another exposure mode is said diaphragm value priority mode.

20. The exposure control apparatus of claim 16, wherein an optimum shutter speed is set with said second APEX value accuracy when said manually actuable switch is actuated and said another exposure mode is said diaphragm value priority mode.

21. The exposure control apparatus of claim 16, wherein an optimum diaphragm value is set with said first APEX value accuracy when said manually actuable switch is actuated and said another exposure mode is said shutter speed priority mode.

22. The exposure control apparatus of claim 16, wherein an optimum diaphragm value is set with said second APEX value accuracy when said manually actuable switch is actuated and said another exposure mode is said shutter speed priority mode.

23. The exposure control apparatus of claim 16, wherein said exposure factors determined by said exposure factor determining means at one of said first APEX value accuracy or said second APEX value accuracy are retained when said manually actuable switch is disabled when said manually actuable switch is in said manual exposure mode.

24. The exposure control apparatus of claim 23, further comprising an indicator that indicates said exposure factors set at said first APEX value accuracy.

25. The exposure control apparatus of claim 2, further comprising limit value setting means, positioned on a camera body of said camera, for varying and setting at least one of an upper limit value and a lower limit value of at least one of said shutter speed and said aperture value.

26. The exposure control apparatus of claim 25, wherein said limit value setting means comprises a plurality of instructions executed by a microprocessor on said camera body.

27. The exposure control apparatus of claim 25, wherein said limit value setting means comprises means for enabling each of said limit values to be set by a single operating member on said camera body.

28. The exposure control apparatus of claim 2, wherein said manual setting means comprises means for setting said aperture value and said shutter speed independently of a luminance of an object to be photographed with said camera.

29. The exposure control apparatus of claim 2, further comprising:

means for locking an exposure value determined in accordance with said aperture value and shutter speed value set in said manual setting mode; and

means for varying one of said aperture value and said shutter speed based on said locked exposure value, when the other of said aperture value and shutter speed is varied by said manual setting means so as to maintain constant said locked exposure value.

30. The exposure control apparatus of claim 2, further comprising a bulb exposure mode.

31. The exposure control apparatus of claim 2, wherein said manual setting means comprises:

means for manually setting a shutter speed while in said automatic mode; and

means for manually setting an aperture value while in said automatic mode, and wherein said exposure factor determining means comprises;

means for automatically determining said shutter speed and said aperture value in accordance with said object brightness metered by said photometering means in said automatic exposure mode, wherein said automatic determining means determines said shutter speed in accordance with a manually set aperture value set by said manually setting aperture value means and said object brightness metered by said photometering means when said aperture value is manually set while in said automatic mode, and wherein said exposure factor determining means determines said aperture value in accordance with a manually set shutter speed set by said manually setting shutter speed means and said object brightness metered by said photometering means when said shutter speed is manually set while in said automatic mode; and

means for returning to said automatic mode in which said shutter speed and aperture value are automatically determined, from a state in which at least one of said shutter speed and said aperture value is set by said manual setting means when said mode modifying switch is operated while in said automatic mode.

32. The exposure control apparatus of claim 31, wherein said camera comprises:

a camera body; and

a photographing lens that is detachably attachable to said camera body, wherein said photometering means, said automatic determining means and said mode modifying switch are provided in said camera body.

33. The exposure control apparatus of claim 32, wherein said manually setting shutter speed means and said manually setting aperture value means are provided in said camera body.

34. The exposure control apparatus of claim 32, wherein said manually setting shutter speed means is provided in said camera body, and said manually setting aperture value means is provided in said photographing lens.

35. The exposure control apparatus of claim 33, further comprising additional means for manually setting said aperture value provided in said photographing lens.

36. The exposure control apparatus of claim 35, wherein said additional manually setting aperture value means in said photographing lens comprises a diaphragm ring movable between an auto-diaphragm position, in which said aperture value is set on said camera body, and a manual diaphragm position, in which said aperture value is set on said photographing lens.

37. The exposure control apparatus of claim 36, wherein said exposure factor determining means determines both said aperture value and said shutter speed in accordance with said object brightness when said diaphragm ring is moved to said auto-diaphragm position.

38. The exposure control apparatus of claim 36, wherein said exposure factor determining means determines said shutter speed in accordance with said object brightness metered by said photometering means and said manually set aperture value when said aperture value is set by said manually setting aperture value means of said camera body while in said automatic mode.

39. The exposure control apparatus of claim 37, wherein said exposure factor determining means determines said shutter speed in accordance with said object brightness metered by said photometering means and said manually set aperture value when said aperture value is set by said additional manually setting aperture value means in said photographing lens while in said automatic mode.

40. The exposure control apparatus of claim 2, wherein said mode modifying switch is operable without moving said camera from a photographing position.

41. The exposure control apparatus of claim 1, wherein said when said manually actuable switch is de-actuated, said at least one automatically set shutter speed and aperture value is replaced with at least one of said manually set shutter speed and aperture value.

66. The exposure control apparatus of claim 2, further comprising:

means for calculating an optimum exposure value in accordance with said detected object brightness;

a specific program exposure mode, in which said shutter speed and said aperture value are automatically set in accordance with said optimum exposure value; and

means for enabling said manual setting means to manually set one of said shutter speed and said aperture value only when said manual setting means is actuated in said specific program exposure mode, said specific program exposure mode being automatically set from among a plurality of exposure modes upon the occurrence of a predetermined event.

67. The exposure control apparatus of claim 66, further comprising a main switch for controlling a power supply to various elements of said camera, said predetermined event comprising turning OFF said main switch.

68. The exposure control apparatus of claim 66, further comprising means for selectively attaching a lens to said camera, wherein said predetermined event comprises an attachment of a lens to said camera.

42. An exposure control apparatus of a camera, comprising:

photometering means for metering a brightness of an object to be photographed;

manual exposure factor setting means for manually setting exposure factors, including a shutter speed and an aperture value, said shutter speed and said aperture value being set with a first APEX value accuracy;

automatic exposure factor setting means for automatically setting exposure factors with a second APEX value accuracy in accordance with said object brightness detected by said photometering means, said second APEX value accuracy being higher than said first APEX value accuracy;

exposure control means for controlling an exposure operation in accordance with said set exposure factors;

exposure factor modifying means for modifying at least one of said shutter speed and said aperture value of said manually set exposure factors to values having said second APEX value accuracy in accordance with said object brightness; and

an exposure factor modifying switch for replacing said manually set exposure factors with automatically set exposure factors when a manual exposure mode is selected and said exposure factor modifying switch is actuated.

43. The exposure control apparatus of claim 42, further comprising means for selecting an exposure mode from among a first mode in which only said shutter speed is automatically set, a second mode in which only said aperture value is automatically set, and a third mode in which both said shutter speed and said aperture value are automatically set.

44. The exposure control apparatus of claim 42, wherein said exposure factor modifying means operates only when said exposure factor modifying switch is actuated.

45. The exposure control apparatus of claim 44, wherein said exposure factor modifying means rounds said automatically set exposure factors to a value with said first APEX value accuracy when said exposure factor modifying switch is deactuated.

46. The exposure control apparatus of claim 44, wherein said exposure factor modifying means retains said automatically set exposure factors, set with said second APEX value accuracy, when said exposure factor modifying switch is deactuated after having been actuated.

47. The exposure control apparatus of claim 46, wherein said automatically set exposure factors, set with said second APEX value accuracy, are retained regardless of a change in object brightness detected by said photometering means, until said manual setting means is operated.

48. The exposure control apparatus of claim 47, wherein said exposure factors are varied with said first APEX value accuracy when said manual setting means is operated after said exposure factor modifying switch is disabled after having been enabled.

49. The exposure control apparatus of claim 44, further comprising exposure factor modifying mode selecting means for selecting one of a first APEX value exposure factor modifying mode in which automatically modified exposure factors set with said second APEX value accuracy are rounded to values with said first APEX value accuracy when said exposure factor modifying switch is disabled after having been enabled, and a second exposure factor modifying mode in which automatically modified exposure factors set with said second APEX value accuracy are retained when said exposure factor modifying switch is disabled after having been enabled.

50. The exposure control apparatus of claim 42, wherein said first APEX value accuracy, settable by said manual exposure factor setting means, comprises an APEX value of 1/2, and said second APEX value accuracy, settable by said automatic exposure factor setting means, comprises an APEX value of 1/8.

51. The exposure control apparatus of claim 50, wherein said manually set APEX value comprises a manual series value consisting of mixed numbers having an antilogarithm portion of 0/2 and 1/2.

52. The exposure control apparatus of claim 50, wherein said automatically set APEX value comprises an automatic series value consisting of mixed numbers having an antilogarithm portion of 0/8.

53. The exposure control apparatus of claim 50, wherein said camera comprises:

a camera body; and

a photographing lens selectively attachable to said camera body, wherein said manual setting means is provided in said camera body.

54. The exposure control apparatus of claim 50, wherein said camera comprises an indicator that indicates at least one of said exposure factors set with said first APEX value accuracy.

55. The exposure control apparatus of claim 50, wherein said indicator rounds said exposure factors to values having said first APEX value accuracy and indicates said exposure factors with said first APEX value accuracy when said exposure factors are set with said second APEX value accuracy.

56. The exposure control apparatus of claim 42, wherein said exposure factor modifying switch is operable without moving said camera from a photographing position.

57. An exposure control apparatus of a camera, comprising:

means for manually setting a shutter speed;

means for manually setting an aperture value;

means for selecting a desired exposure mode from among a plurality of automatic exposure modes and a manual exposure mode, said selected automatic exposure mode determining optimum exposure factors based upon at least one of said shutter speed and said aperture value in accordance with an object brightness of an object to be photographed, while said selected manual exposure mode sets said shutter speed and said aperture value in accordance with said manually setting shutter speed means and said manually setting aperture value means;

means for modifying said desired exposure mode selected by said selecting means; and

means for replacing exposure factors based upon said manually set shutter speed and said manually set aperture value with said optimum exposure factors when said desired exposure mode is switched from said selected automatic exposure mode to said manual exposure mode and said modifying means is actuated.

58. The exposure control apparatus of claim 57, wherein when said automatic exposure mode is selected by said selecting means, said operation of said manually setting shutter speed means causes a change in an automatic determination of said aperture value.

59. The exposure control apparatus of claim 57, wherein when said automatic exposure mode is selected by said selecting means, said operation of said manually setting aperture value means causes a change in an automatic determination of said shutter speed.

60. The exposure control apparatus of claim 57, wherein said plurality of automatic exposure modes includes a mode wherein upper and lower limits of said shutter speed and upper and lower limits of said aperture value are modifiable by a user of said camera.

61. The exposure control apparatus of claim 57, wherein said manual modifying means is operable without moving said camera from a photographing position.

62. An exposure controlling apparatus, comprising:

means for manually setting a shutter speed with a first APEX value accuracy;

means for manually setting an aperture value with a second APEX value accuracy, a manual exposure factor being defined in accordance with said manually set shutter speed and said manually set aperture value;

means for setting a shutter speed and a diaphragm value that define an automatic exposure factor with a predetermined APEX value accuracy based upon a brightness of an object to be photographed;

means for modifying said automatically set exposure factor based upon at least one of said manually set shutter speed and said manually set aperture value; and

means for switching a manual exposure factor with said automatic exposure factor to effect an exposure operation of said object in which said shutter speed and aperture value are set in accordance with said object brightness when a nonprogrammed exposure mode is selected and said switching means is actuated.

63. The exposure controlling apparatus of claim 62, wherein said first APEX value accuracy is less than said second APEX value accuracy.

64. The exposure controlling apparatus of claim 63, further comprising means for modifying at least one of said manually set shutter speed or said manually set aperture value to have said second APEX value accuracy.

65. The exposure controlling apparatus of claim 62, further comprising means for selecting an exposure mode from among a first mode in which said shutter speed is automatically set, a second mode in which said aperture value is automatically set, and a third mode in which both said shutter speed and said aperture value are automatically set.

69. The exposure control apparatus of claim 62, wherein said modifying means is operable without moving said camera from a photographing position.

70. An exposure control apparatus of a camera, comprising:

photometering means for metering a brightness of an object to be photographed;

means for manually setting a shutter speed;

means for manually setting an aperture value;

mode changing means for selecting an exposure mode from among a plurality of exposure modes, including a manual exposure mode in which a shutter speed and an aperture value are manually set by said manually setting shutter speed means and by said manually setting aperture value means, and an automatic exposure mode in which at least one of said shutter speed and said aperture value is automatically set in accordance with an other of said at least one of said shutter speed and said aperture value, and said object brightness;

exposure factor determining means for determining an optimum exposure value in response to said metered object brightness, said exposure factor determining means being actuated when a presently selected mode is said automatic exposure mode; and

a manually actuable switch for replacing an exposure factor related to said manually set shutter speed and manually set aperture value with said optimum exposure factor when said manually actuable switch is actuated while the presently selected mode is said manual exposure mode.

71. The exposure control apparatus of claim 70, wherein said when said manually actuable switch is de-actuated, said at least one automatically set shutter speed and aperture value is replaced with at least one of said manually set shutter speed and aperture value.