Apparatus for photographing that carries out a pre-flash photography

Patent metadata

Field	Value
Publication number	US-9456145-B2
Application number	US-201414317454-A
Country	US
Kind code	B2
Filing date	Jun 27, 2014
Priority date	Jul 3, 2013
Publication date	Sep 27, 2016
Grant date	Sep 27, 2016

Abstract

An apparatus for photographing by using an electronic flash has a photography controller that carries out a pre-flash photography by emitting strobe light in a pre-flash exposure period and subsequently carries out a main flash photography by emitting strobe light; and an exposure adjuster that sets at least one exposure value associated with the pre-flash photography and/or the main flash photography. The exposure adjuster sets an aperture value of a diaphragm that suppresses an occurrence of saturation in image-pixel signals that are generated in an image sensor in the pre-flash exposure period. The photography controller drives the diaphragm in accordance to the set aperture value for the pre-flash photography.

First claim

The invention claimed is:

1. An apparatus for photographing by using an electronic flash, comprising:
a photography controller that carries out a pre-flash photography by emitting strobe light in a pre-flash exposure period and subsequently carries out a main flash photography by emitting strobe light;
an exposure adjuster that sets at least one exposure value, said exposure adjuster setting an aperture value of a diaphragm that suppresses an occurrence of saturation in image-pixel signals that are generated in an image sensor in the pre-flash exposure period, said photography controller driving said diaphragm in accordance to the set aperture value for the pre-flash photography, and
an image sensor driver that drives said image sensor, said photography controller controls said image sensor driver to set the pre-flash exposure period to be shorter than an exposure period in one frame/field interval during a through-mode.

2. The apparatus of claim 1 , wherein the exposure adjuster sets a maximum value among aperture values that are capable of suppressing saturation in the image-pixel signals when carrying out the pre-flash photography.

3. The apparatus of claim 1 , wherein said exposure adjuster determines whether the aperture value can be set to a full-open aperture value.

4. The apparatus of claim 3 , wherein said exposure adjuster determines whether the aperture value can be set to a full-open aperture value based on stationary light.

5. The apparatus of claim 4 , wherein said exposure adjuster determines whether the aperture value can be set to a full-open position on the basis of the brightness of an object that is measured and the brightness of an object that is calculated on the basis of APEX system.

6. The apparatus of claim 3 , wherein said exposure adjuster determines whether the aperture value can be set to a full-open aperture value based on the distance of an object.

7. The apparatus of claim 6 , wherein said exposure adjuster determines whether the aperture value can be set to a full-open aperture value on the basis of a provisional distance of an object that is obtained by an AF process and a calculated distance of an object that is calculated in accordance to a relationship between a Guide Number and the sensitivity of said image sensor and a relationship between a Guide Number and an aperture value.

8. The apparatus of claim 3 , wherein said exposure adjuster adjusts a gain value for the image-pixel signals such that an output level of image pixel signals that are used for obtaining the distance of an object becomes an output level within the dynamic range of said image sensor.

9. The apparatus of claim 8 , wherein said exposure adjuster increases the gain value such that an output level of image-pixel signals that are used for obtaining the distance of an object becomes an output level within a middle range among the dynamic range of said image sensor.

10. The apparatus of claim 9 , wherein said exposure adjuster determines whether output levels of the image-pixel signals that are subjected to a gain process based on the adjusted gain value reach a saturation level.

11. The apparatus of claim 1 , wherein said photography controller changes at least one of a frame rate and an interval of pixel decimation.

12. The apparatus of claim 1 , wherein said photography controller drives said strobe light in accordance to an amount of strobe light based on the sensitivity of said image sensor.

13. The apparatus of claim 1 , wherein said exposure adjuster sets an aperture value in response to a value associated with an exposure, the value being detected when a release button is depressed halfway.

14. An apparatus for photographing by using an electronic flash, comprising:
a photography controller that carries out a pre-flash photography by emitting strobe light in a pre-flash exposure period and subsequently carries out a main flash photography by emitting strobe light; and
an exposure adjuster that sets at least one exposure value, said exposure adjuster setting an aperture value of a diaphragm that suppresses an occurrence of saturation in image-pixel signals that are generated in an image sensor in the pre-flash exposure period, said photography controller driving said diaphragm in accordance to the set aperture value for the pre-flash photography,
wherein said image sensor comprises an X-Y address type image sensor using a rolling shutter method, said photography controller raising a ratio of the pre-flash exposure period to one frame/field interval relative to a ratio during a through mode to allow all of the pixel-lines in said image sensor to be exposed by strobe light in the pre-flash photography.

15. An apparatus for photographing by using an electronic flash, comprising:
a photography controller that carries out pre-flash photography by emitting strobe light in a pre-flash exposure period and subsequently carries out main flash photography by emitting strobe light;
an exposure adjuster that sets at least one exposure value, said exposure adjuster setting an aperture value of a diaphragm that suppresses an occurrence of saturation in image pixel signals that are generated in an image sensor in the pre-flash exposure period, said photography controller driving said diaphragm in accordance with the set aperture value for the pre-flash photography, said exposure adjuster adjusts an aperture value to a value that suppresses an occurrence of saturation before performing pre-flash photography; and
said exposure adjuster controls the diaphragm such that an opening degree of the diaphragm corresponds to the adjusted aperture value when performing pre-flash photography.

16. The apparatus of claim 15 , further comprising an image sensor driver that drives said image sensor, said photography controller controls said image sensor driver to set the pre-flash exposure period that is shorter than an exposure period in one frame/field interval during a through-mode.

17. The apparatus of claim 15 , wherein said exposure adjuster determines whether the aperture value can be set to a full-open aperture value.

18. The apparatus of claim 17 , wherein said exposure adjuster determines whether the aperture value can be set to a full-open aperture value based on stationary light.

19. The apparatus of claim 17 , wherein said exposure adjuster determines whether the aperture value can be set to a full-open aperture value based on the distance of an object.

20. The apparatus of claim 17 , wherein said exposure adjuster adjusts a gain value for the image-pixel signals such that an output level of image pixel signals that are used for obtaining the distance of an object becomes an output level within the dynamic range of said image sensor.

Assignees

• Ricoh Imaging Co Ltd

Inventors

• Ueno Hirotaka

Classifications

• H04N23/76

  by influencing the image signals · CPC title

• G03B7/17 Primary

  Selection of modes in flash units by exposure control arrangements · CPC title

• H04N23/74 Primary

  by influencing the scene brightness using illuminating means · CPC title

• H04N23/75

  by influencing optical camera components · CPC title

• G03B7/08

  Control effected solely on the basis of the response, to the intensity of the light received by the camera, of a built-in light-sensitive device · CPC title