Camera having light-source determining function

• US 5,621,494 A
• Filed: 10/19/1994
• Issued: 04/15/1997
• Est. Priority Date: 10/25/1993
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Yokoyama, Kenji, Kazumi, Jiro, Nagata, Toru
• Primary Examiner(s): Perkey, W. B.
• Application Number:
  US08/325,885
• Time in Patent Office: 909 Days
• Field of Search: 354/430, 354/416, 354/417, 354/402, 354/403, 354/266, 354/202, 348/211-214, 348/224-228, 348/349, 348/370
• US Class Current: 396/56
• CPC Class Codes: G03B 7/097 for control of both exposure time and aperture

Abstract

The present invention relates to a camera having a light-source determining function for determining the kind of light source. According to the present invention, the light-source determining function of the camera is realized by using the output of a light receiving part of a remote control processing part of the camera.

Claims

1. A camera comprising:

(a) a light measuring circuit which measures a light measuring value for exposure control;

(b) a light receiving circuit different from the light measuring circuit;

(c) a first processing circuit for processing an output of said light receiving circuit for implementing a predetermined function of said camera; and

(d) a second processing circuit for determining a kind of light source of light received by said light receiving circuit on the basis of the output of said light receiving circuit.

2. A camera according to claim 1, wherein said camera includes remote control circuitry and wherein said light receiving circuit is a light receiving circuit for said remote control circuitry and is adapted to receive a light signal for remote control.

3. A camera according to claim 1, wherein said camera includes autofocus circuitry and wherein said light receiving circuit is a light-receiving sensor circuit for said autofocus circuitry.

4. A camera according to claim 1, wherein said camera includes flash unit and wherein said light receiving circuit is a light-receiving sensor circuit for controlling an amount of flash emission and is adapted to receive light reflected from a subject after being emitted from said flash unit.

5. A camera according to claim 1, wherein said second processing circuit determines the kind of light source according to an amplitude of the output of said light receiving circuit or a difference between a maximum value and a minimum value of the output of said light receiving circuit.

6. A camera according to claim 1, wherein said second processing circuit determines the kind of light source on the basis of the output of said light measuring circuit and the output of said light receiving circuit.

7. A camera according to claim 6, wherein said camera includes remote control circuitry and wherein said light receiving circuit is a light receiving circuit for said remote control circuitry and is adapted to receive a light signal for remote control.

8. A camera according to claim 4, wherein said second processing circuit includes integrating means for integrating an output of said light-receiving sensor circuit and computing means for finding an amount of variation per unit time in an integral value provided by said integrating means, said second processing circuit determining the kind of light source according to a difference between a maximum amount of variation and a minimum amount of variation from among amounts of variations obtained by said computing means.

9. A camera having a remote control circuit which receives a light signal for remote control, comprising:

(a) a light receiving circuit for receiving the light signal;

(b) switching means for switching a light receiving characteristic of said light receiving circuit between a first characteristic which allows said light receiving circuit to pass a frequency contained in a first frequency band and a second characteristic which allows said light receiving circuit to pass a frequency contained in a second frequency band;

(c) a remote control processing circuit for performing a remote control function according to an output which is provided by said light receiving circuit when the light receiving characteristic of said light receiving circuit is switched to the first characteristic; and

(d) a decision circuit for determining the kind of light source on the basis of the output which is provided by said light receiving circuit when the light receiving characteristic of said light receiving circuit is switched to the first characteristic and an output which is provided by said light receiving circuit when the light receiving characteristic of said light receiving circuit is switched to the second characteristic.