Digital camera having a continuous photography mode

• US 20020018142A1
• Filed: 06/05/2001
• Published: 02/14/2002
• Est. Priority Date: 06/15/2000
• Status: Active Grant

• Current Assignee: Minolta Corporation Limited (Konica Minolta Inc.)
• Original Assignee: Minolta Corporation (Konica Minolta Inc.)
• Inventors: Oda, Katsunari
• Granted Patent: US 6,636,263 B2
• Time in Patent Office: Days
• US Class Current: 348/370
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means
• CPC Class Codes: H04N 23/76 by influencing the image signals

Abstract

When the flash emission mode is set in continuous photography, the amount of emission of the built-in flash during continuous photography and the charge amount of the main condenser needed to realize this light emission are estimated. The gain is increased from a standard value when the charging time for obtaining the aforesaid charge amount is greater than the continuous frame speed. In this way continuous photography is accomplished while the shutter button is fully pressed without reducing the continuous frame speed.

Claims

1. A digital camera having a continuous photography mode, comprising:

an image sensor for sensing an object image;

a light emission device for illuminating the object during photography;

a chargeable power source for supplying power to the light emission device;

an adjustor for adjusting a gain of the output of the image sensor;

a determining portion for determining an amount of light emission of the light emission device in the photography;

a charge time calculator for calculating a charge time of the power source needed after light emission based on the determined amount of light emission;

a discriminator for discriminating whether or not a frame speed in the continuous photography mode is reduced based on the calculated charge time; and

a gain controller for controlling the adjuster so as to increase the gain when it has been discriminated that the frame speed is reduced.

2. The digital camera according to claim 1, wherein the determining portion determines the amount of light emission based on a luminance of the object.

3. The digital camera according to claim 2, wherein the determining portion comprises a light emission controller for executing a pre-light emission by the light emission device before photography and a luminance detector for detecting a luminance of an object under the pre-light emission, and the determining portion determines the amount of light emission based on the detected object luminance.

4. The digital camera according to claim 2, wherein the determining portion comprises a luminance detector for detecting a luminance of an object and a distance detector for detecting a distance to the object, and the determining portion determines the amount of light emission based on the detected object luminance and the detected distance.

5. The digital camera according to claim 1, wherein the gain controller restores the increased gain to an original value after the photography.

6. A method of gain control of a digital camera having a continuous photography mode, comprising:

determining an amount of light emission of a light emission device in the photography;

calculating a charge time of a power source of the light emission device needed after light emission based on the determined amount of light emission;

discriminating whether or not a frame speed in the continuous photography mode is reduced based on the calculated charge time; and

controlling a gain of output of an image sensor element so as to increase the gain when it has been discriminated that the frame speed is reduced.