Display device for camera

• US 4,299,463 A
• Filed: 09/28/1979
• Issued: 11/10/1981
• Est. Priority Date: 10/05/1978
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Shigeta, Yoshihiro, Kawamura, Masaharu
• Primary Examiner(s): Hix, L. T.
• Assistant Examiner(s): Perkey, William B.
• Application Number:
  US06/080,798
• Time in Patent Office: 774 Days
• Field of Search: 354/127, 354/128, 354/139, 354/149, 354/289, 354/273, 354/32-34, 354/60 F, 354/60 L, 354/53
• US Class Current: 396/203
• CPC Class Codes: G03B 17/20 visible in viewfinder

Abstract

In the disclosed system, a camera of the type which manually presets a diaphragm aperture and particularly for a camera which operates with a computer flash device. For flash operation, the aperture of such a camera must be set at a value suitable for the flash device. A signal representative of an aperture value suitable for the computer flash device and a signal representative of a preset aperture value are compared and, when these two values coincide with each other, the coincidence is displayed by a display device arranged within the view finder to let the photographer know that the camera has been set at an aperture value required for flash photography.

Claims

1. A camera system comprising:

(A) a flash device including;

flash photography aperture value signal forming means for producing a first aperture value signal; and

(B) a camera including;

(a) aperture presetting means for presetting an aperture value and for producing a second aperture value signal;

(b) a detection circuit for detecting the aperture value signal produced by said flash photography aperture value signal forming means and the second aperture value signal representative of an aperture value set by said aperture presetting means, said detection circuit being arranged to produce a coincidence signal when said two aperture value signals coincide with each other; and

(c) an indicating circuit for indicating an aperture presetting status in response to said coincidence signal produced by said detection circuit.

3. A camera system according to claim 1 or claim 2, wherein said flash device includes a main capacitor and a charging completion signal forming circuit for detecting the status of a charging process on said main capacitor and for producing a charging completion signal when said main capacitor reaches a predetermined charged state;

said indicating circuit being arranged to become operative in response to said charging completion signal.

2. A camera system comprising:

(A) a flash device including;

(a) flash photography aperture value selecting means

(b) flash photography aperture value signal forming means for producing a first aperture value signal corresponding to an aperture value selected by said flash photography aperture value selecting means; and

(B) a camera including;

(a) aperture presetting means for presetting an aperture value and for producing a second aperture value signal;

(b) a detection circuit for detecting the first aperture value signal produced by said flash photography aperture value signal forming means and the second aperture value signal representative of an aperture value set by said aperture presetting means, said detection circuit being arranged to produce a coincidence signal when said two aperture value signals coincide with each other, and

(c) an indicating circuit for indicating an aperture presetting status in response to said coincidence signal produced by said detection circuit.

4. A camera system comprising:

(A) a indicating flash device including;

(a) accumulating means for accumulating flash energy;

(b) a ready-for-flash signal forming means for detecting the level of the energy accumulated in said accumulating means and for producing a ready-for-flash signal when said energy level reaches a predetermined value; and

(c) flash photography aperture value signal forming means for forming a first aperture value signal representative of an aperture value required for flash photography; and

(B) a camera including;

(a) aperture presetting means for presetting an aperture value forming a second aperture value signal representative of an aperture value;

(b) a detection circuit for detecting the first aperture value signal produced by said flash photography aperture value signal forming means and the second signal representative of the aperture value set by said aperture presetting means, said detection circuit being arranged to produce a coincidence signal when said two aperture value signals coincide with each other;

(c) a display circuit which displays a ready-for-flash signal and

(d) said display circuit being arranged to vary the display state thereof in response to said coincidence signal and thus to indicate that the aperture value set by said aperture presetting means has reached the aperture value required for flash photography.

5. A camera system according to claim 4, wherein said display circuit includes pulse signal forming means, display means, and driving means for driving said display means on a periodic basis according to the pulses produced by said pulse signal forming means and for continuously driving said display means in response to said ready-for-flash signal and said coincidence signal.

6. A camera usable in combination with a flash device having flash photography aperture value information producing means for producing aperture value information representing a first aperture value for flash photography, said camera comprising:

(a) aperture presetting means for presetting an aperture value and for producing preset aperture value information; and

(b) indicating means responsive to said flash photography aperture value information and the preset aperture value information from said aperture presetting means for indicating coincidence when said two aperture values coincide.

7. A camera usable in combination with a flash device having flash photography aperture value signal forming means for producing a flash photography aperture value signal, said camera comprising:

(a) aperture presetting means for presetting an aperture value and for producing an aperture value signal;

(b) a detection circuit for detecting an aperture value signal produced by said flash photography aperture value signal forming means and an aperture value signal representative of an aperture value set by said aperture presetting means, said detection circuit being arranged to produce a coincidence signal when said two aperture value signals coincide; and

(c) an indicating circuit which displays an aperture presetting status in response to the coincidence signal produced by said detection circuit.

8. A camera usable with a flash device having flash photography aperture value signal forming means for producing a first aperture value signal representing an aperture value required for flash photography and ready-for-flash signal forming means for producing a ready-for-flash signal when the level of energy accumulated in the flash energy accumulating means reaches a predetermined value, said camera comprising:

(a) indicating means for indicating a ready condition for flash in response to said ready-for-flash signal;

(b) aperture presetting means for presetting an aperture value and for producing a second aperture value signal representative of the aperture value;

(c) a detection circuit for detecting said first aperture value signal for flash photography and said second aperture value signal representative of the aperture value prreset by said aperture presetting means, said detection circuit being arranged to produce a coincidence signal when said two aperture value signals coincide; and

(d) an indicating control circuit for varying the indicating mode of said indicating means in response to said coincidence signal to indicate that the aperture value set by said aperture presetting means coincides with said aperture value required for flash photography.

9. A camera system comprising:

(a) aperture presetting means for presetting an aperture value and for producing an aperture value signal representative of the preset aperture value;

(b) flash photography aperture value forming means for producing a flash photography aperture value signal representative of an aperture value required for flash photography;

(c) a detection circuit for detecting said flash photography aperture value signal and the aperture value signal representative of an aperture value set by said aperture presetting means, said detection circuit being arranged to produce a coincidence signal when said two aperture value signals coincide; and

(d) indicating means for indicating, in response to said coincidence signal, that the aperture has been preset at an aperture value required for flash photography.