Auto-bracket device for camera

• US 4,862,205 A
• Filed: 07/29/1987
• Issued: 08/29/1989
• Est. Priority Date: 08/01/1986
• Status: Expired due to Term

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Kawamura, Masaharu
• Primary Examiner(s): Perkey, W. B.
• Application Number:
  US07/079,127
• Time in Patent Office: 762 Days
• Field of Search: 354/410, 354/412, 354/173.1, 354/173.11, 354/217, 354/218, 354/442, 354/458, 354/475, 354/444, 354/238.1, 354/445, 354/266, 354/215, 354/441
• US Class Current: 396/222
• CPC Class Codes: G03B 17/40 with delayed or timed action
• CPC Class Codes: G03B 7/097 for control of both exposure time and aperture

Abstract

An auto-bracket device automatically shifts exposure of each frame by a predetermined amount in a multi-frame photographing mode. When multi-frame photographing is done in an auto-bracket mode, even if a shutter release button is released in the course of the auto-bracket mode photographing, the auto-bracket mode photographing is continued until a preset number of frames are photographed in the auto-bracket mode.

Claims

1. An auto-bracket device for a camera for repeatedly carrying out a continuous exposure operation by an exposure control circuit and film feeding by a film feed circuit during manual actuation of a shutter release member, comprising:

(a) a variable exposure control circuit for varying a control exposure for each exposure control in an auto-bracket mode exposure control by said exposure control circuit;

(b) a detection circuit for detecting the number of photographing operations in the auto-bracket mode for determining whether a predetermined number of frames have been photographed with different exposures by said variable exposure control circuit; and

(c) an auto-bracket control circuit for causing the repetitive exposure operation in the auto-bracket mode until the end of photographing the predetermined number of frames is detected by said detection circuit, irrespective of the state of the shutter release member, and for stopping the repetitive exposure operation at the end of the photographing of the predetermined number of frames.

2. An auto-bracket device for a camera according to claim 1 wherein the camera includes a release signal generation circuit for generating a first signal when the shutter release member is actuated and a second signal when the shutter release member is not actuated, and a repetition control circuit for causing the repetitive exposure operation and film feed operation in response to the first signal and inhibiting the repetitive operations in response to the second signal, and wherein said auto-bracket control circuit inhibits the response of said repetition control circuit to the second signal and causes said repetition control circuit to respond to the detection output of said detection circuit and inhibits the repetitive operations.

3. An auto-bracket device for a camera according to claim 2 further comprising an exposure correction circuit for manually setting exposure correction, wherein said variable exposure control circuit shifts the exposure for each photographing operations in according with exposure correction information set by said exposure control circuit, and wherein said detection circuit detects the number of photographing operations.

4. An auto-bracket device for a camera according to claim 2 wherein the camera includes a display circuit for displaying exposure information for each photographing operation controlled by said variable exposure control circuit.

5. An auto-bracket device for a camera according to claim 2 wherein said camera includes display means for displaying the shift of the exposure for each photographing controlled by said variable exposure control circuit.

6. An auto-bracket device for a camera according to claim 2 wherein said exposure control circuit controls a shutter speed and a diaphragm in accordance with a shutter speed and a diaphragm manually preset in a manual mode, and wherein said variable exposure control circuit fixes the preset diaphragm for each exposure control and varies the shutter speed for each exposure control in the manual mode.

7. An auto-bracket device for a camera according to claim 1 wherein the camera includes selection means for selecting the auto-bracket mode, wherein said variable exposure control circuit and said auto-bracket control circuit are activated when the auto-bracket mode is selected, and wherein the camera further includes release means for releasing the selection of the auto-bracket mode in response to the inhibition of the repetitive operation under the control of the auto-bracket control circuit in the auto-bracket mode.

8. An auto-bracket device for a camera according to claim 7 wherein the camera includes data setting means for setting correction data for determining the shift of the exposure for each photographing operation by said variable exposure control circuit, said data setting means holding the correction data independently from the release of the selection of the auto-bracket mode by said release means.

9. A camera comprising:

(a) a release member for starting a release operation;

(b) an exposure control circuit for controlling the exposure of an exposure operation started by the release operation;

(c) a film feed circuit activated after the end of the control of the exposure by said exposure control circuit to feed a film;

(d) an exposure operation control circuit for starting the exposure operation at the end of film feeding by said film feed circuit when said release member is actuated;

(e) selection means for selecting an auto-bracket mode;

(f) an exposure shift circuit activated when the auto-bracket mode is selected,

said exposure shift circuit shifting the exposure for each photographing operation when said exposure control circuit controls the exposure;

(g) a detection circuit for detecting the number of photographing operations in the auto-bracket mode and producing an output when it reaches a predetermined number; and

(h) an auto-bracket control circuit for causing said exposure operation control circuit to control the start of the exposure operation after the film feeding in the auto-bracket mode, until said detection circuit generates the output, irrespective of the state of said release member, and inhibiting said start control upon generation of the output of said detection circuit.

10. A camera having an auto-bracket mode in which the amount of exposure is changed for each successive frame, said camera comprising:

(a) a self-timer mode setting member;

(b) an auto-bracket mode setting member for setting the auto-bracket mode;

(c) a timer circuit for measuring predetermined time, said timer circuit being selected when the self-timer mode is set by said self-timer mode setting member;

(d) a control circuit having a first mode in which each successive photographing operation is performed at intervals of time period determined by said timer circuit when said timer circuit is selected, and having a second mode in which successive photographing operations are continuously performed irrespective of the time period determined by said timer circuit when said timer circuit is not selected; and

(e) a selection circuit for making said timer circuit unselected by the auto-bracket mode being set even when the self-timer mode has been set.