Image pickup apparatus with distance measurement dependent on object lighting condition

• US 6,426,775 B1
• Filed: 09/16/1996
• Issued: 07/30/2002
• Est. Priority Date: 09/20/1995
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kurokawa, Shinji
• Primary Examiner(s): Garber, Wendy R.
• Assistant Examiner(s): NGUYEN, LUONG TRUNG
• Application Number:
  US08/714,190
• Time in Patent Office: 2,143 Days
• Field of Search: 348/362, 348/363, 348/364, 348/366, 348/370, 348/371, 348/372, 348/348, 396/61, 396/65, 396/67, 396/69, 396/89, 396/157, 396/159, 396/161, 396/165, 396/170
• US Class Current: 348/363
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means
• CPC Class Codes: H04N 23/75 by influencing optical camera components

Abstract

An image pickup apparatus is provided with an image sensor, a light emission part for illuminating an object by emitting light, a light measuring part for measuring a luminance of the object on the basis of a signal from the image sensor, a distance measuring part for measuring a distance to the object, an operation member for performing a first operation and a second operation for picking up an image of the object, and a control part for controlling the image sensor, the light emission part, the light measuring part and the distance measuring part in response to the first operation and the second operation of the operation member. In response to the first operation of the operation member, the control part causes the light measuring part to measure the luminance, determines whether or not light emission by the light emission part is necessary according to information on the luminance measured by the light measuring part and causes the distance measuring part to measure the distance, and in response to the second operation of the operation part, if light emission by the light emission part is necessary, the control part first controls an iris on the basis of information on the distance measured by the distance measuring part, causes the light emission part to emit light for a predetermined period of time and causes a preliminary exposure to be made on the image sensor, and then the control part causes the light emission part to emit light for a period of time decided on the basis of information on the luminance measured by the light measuring part during the preliminary exposure and causes a main exposure to be made on the image sensor.

Claims

1. An image pickup apparatus comprising;

image pickup means;

light emission means for illuminating an object by emitting light;

light measuring means for measuring a luminance of the object on the basis of a signal from said image pickup means;

distance measuring means for automatically measuring a distance information to the object;

operation means for performing a first operation and a second operation for picking up an image of the object; and

control means for controlling said image pickup means, said light emission means, said light measuring means, and said distance measuring means in response to the first operation and the second operation of said operation means,

wherein, in response to the first operation of said operation means, said control means causes said light measuring means to measure the luminance, determines whether or not light emission by said light emission means is necessary according to information on the luminance measured by said light measuring means and causes said distance measuring means to automatically measure the distance to the object, and in response to the second operation of said operation means, if light emission by said light emission means is necessary, said control means first controls to determine according to a current shooting mode of said image pickup apparatus an iris value for a preliminary exposure by using the distance information outputted from said distance measuring means according to a predetermined function, causes said light emission means to perform a fixed amount of preliminary light emission and causes the preliminary exposure to be made on said image pickup means with the iris value determined according to the distance information, and then said control means causes said light emission means to perform a main light emission for a period of time decided on the basis of information of the luminance value measured by said light measuring means during the preliminary exposure and causes a main exposure to be made on said image pickup means.

2. An image pickup apparatus comprising:

image pickup means;

light emission means for illuminating an object by emitting light;

light measuring means for measuring a luminance of the object on the basis of a signal from said image pickup means;

distance measuring means for measuring a distance to the object;

operation means for performing a first operation and a second operation for picking up an image of the object; and

control means for controlling said image pickup means, said light emission means, said light measuring means and said distance measuring means in response to the first operation and the second operation of said operation means,

wherein, in response to the first operation of said operation means, said control means causes said light measuring means to measure the luminance, determines whether or not light emission by said light emission means is necessary according to information on the luminance measured by said light measuring means and causes said distance measuring means to measure the distance, and in response to the second operation of said operation means, if light emission by said light emission means is necessary, said control means first controls an iris into an aperture value having a greater amount of stopping-down selected from between an aperture value decided on the basis of information on the distance measured by said distance measuring means and an aperture value decided on the basis of a program diagram, causes said light emission means to emit light for a predetermined period of time and causes a preliminary exposure to be made on said image pickup means, and then said control means causes said light emission means to emit light for a period of time decided on the basis of information on the luminance measured by said light measuring means during the preliminary exposure and causes a main exposure to be made on said image pickup means.

3. An apparatus according to claim 2, wherein said control means is arranged to change over an aperture value according to a current shooting mode of said image pickup apparatus when controlling the iris on the basis of information on the distance.

4. An apparatus according to claim 2, wherein said light emission means is a flash device.

5. An apparatus according to claim 2, wherein said operation means is a shutter release switch.

6. An apparatus according to claim 2, wherein said control means is arranged to decide an aperture value of the iris on the basis of information on the distance measured by said distance measuring means, so that a predetermined amount of reflected light from the object can be obtained when a fixed amount of light is emitted by said light emission means.

7. An image pickup apparatus comprising:

image pickup means;

light emission means for illuminating an object by emitting light;

light measuring means for measuring a luminance of the object;

distance measuring means for automatically measuring a distance information to the object; and

control means for causing said light measuring means to measure the luminance, and determine whether or not light emission by said light emission means is necessary according to information on a first luminance value measured by said light measuring means and causing said distance measuring means to automatically measure the distance information, said control means, in the case that light emission is determined to be necessary, causing said light emission means to perform a fixed amount of preliminary light emission with an iris value computed by using the distance information outputted from said distance measuring means according to a current shooting mode of said image pickup apparatus and causing said light measuring means to measure a second luminance value during the preliminary light emission, and determining a light amount of main light emission of said light emission means on the basis of the second luminance value.