Electric control camera

• US 5,005,042 A
• Filed: 01/25/1990
• Issued: 04/02/1991
• Est. Priority Date: 03/26/1987
• Status: Expired due to Term

• Current Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
• Original Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
• Inventors: Sato, Osamu, Hirai, Isamu
• Primary Examiner(s): Adams, Russell E.
• Application Number:
  US07/471,013
• Time in Patent Office: 432 Days
• Field of Search: 354/412, 354/413, 354/416, 354/417, 354/420, 354/422, 354/423, 354/435, 354/441, 354/446, 354/400, 354/402
• US Class Current: 396/67
• CPC Class Codes: G03B 7/16 in accordance with both the intensity of the flash source and the distance of the flash source from the object, e.g. in accordance with the "guide number" of the flash bulb and the focusing of the camera
• CPC Class Codes: G03B 7/24 automatically in accordance with markings or other means indicating film speed or kind of film on the magazine to be inserted in the camera

Abstract

An electronic control camera in which, when an electronic flash is used with the camera, the required exposure data is automatically set. In the electronic control camera to which the invention pertains, film sensitivity data and luminance data provided by a photometric unit are applied to a data processing unit, which utilizes those tow data values to control the shutter speed and/or the aperture value. Further, the data processing unit varies the shutter speed, the aperture value and/or the amount of light emitted by the electronic flash coupled to the camera in accordance with these two data values.

Claims

1. A camera having a built-in flash comprising:

(a) film sensitivity data input means (5) for inputting sensitivity data (SV) of a film inserted into said camera;

(b) shutter means settable in accordance with shutter speed values TV;

(c) diaphragm aperture means settable in accordance with aperture values AV;

(d) photometric means (15) for determining the brightness value BV of an object to be photographed by said camera;

(e) distance setting means for setting distance values DV of the object;

(f) data processing means (1) connected to said film sensitivity data input means (5) and to said photometric means (15) for calculating an exposure value EV in accordance with said film sensitivity data value SV and with said brightness value BV;

(g) said data processing means being operable for determining whether said exposure value EV is larger than a first predetermined value, and when said exposure value EV is larger than the first predetermined value, said data processing means varies the amount of light emitted by said flash according to said exposure value EV, flash photographing is carried out with a shutter speed at a first constant value, and an aperture value is calculated according to the following expression;

space="preserve" listing-type="equation">AV=AVs+(SV-SVs)-α

(DV-DVs)

wherein AVs, SVs and DVs are initially set values for the values AV, SV, and DV, respectively, when not yet available, and wherein α

is a coefficient.

2. The camera as defined in claim 1, wherein said aperture value AV is within a range defined by a maximum value and a minimum value.

3. The camera as defined in claim 2, wherein said aperture value AV is kept with the range, and said data processing means is operable to make the aperture value AV equal to the difference (EV -TV) between the exposure value EV and the shutter speed value TV if said difference (EV-TV) is not higher than said aperture value AV, and said data processing means is operable to employ the aperture value AV unchanged if said difference (EV-TV) is higher than said aperture value AV.

4. The camera as defined in claim 3, wherein said aperture value AV is set according to the following expression:

space="preserve" listing-type="equation">AV=AVs+(SV-SVs)+(XVs-SV)-α

(DV-DVs)

wherein XVs is an initially set value for a correction value XV, when not yet available.

5. The camera as defined in claim 1, wherein, in the case where said exposure value EV is not higher than a first predetermined value, but higher than a second predetermined value, said data processing means varies the amount of light emitted by said flash according to said exposure value EV, flash photographing is carried out with an aperture value AV set to a minimum value of a predetermined range thereof, and a shutter speed value TV set equal to a first value corresponding to the minimum of said exposure value.

6. The camera as defined in claim 1, wherein, in the case where said exposure value EV is not higher than the second predetermined value, said data processing means varies the amount of light emitted by said flash according to said exposure value EV, flash photographing is carried out with an aperture value AV set according to the following expression, and a shutter speed TV is made smaller than said first value,

7. The camera as defined in claim 6, wherein the aperture value AV is within a range defined by a maximum value and a minimum value.

8. The camera as defined in claim 7, wherein said aperture value AV is kept with the range, and said data processing means is operable to make the aperture value AV equal to the difference (EV -TV) between the exposure value EV and the shutter speed value TV, if said difference (EV-TV) is higher than said aperture value AV, and to employ the aperture value AV unchanged if said difference (EV-TV) is not higher than said aperture value AV.