Electronic camera having an automatic electric flash function
An electronic camera, which is capable of obtaining a more appropriate exposure even when taking a picture by an electric flash photograph, comprises a light emission section for emitting a preliminary light prior to a main photograph and emitting a main light upon taking a picture with respect to a object, a pickup device for receiving an object image in the preliminary light emission and converting a light into electricity to obtain a photograph signal, an amplifying section for amplifying the photograph signal which is obtained by the pickup device and a setting section for setting a gain of the amplifying section and a light emission amount in the main light emission on the basis of the photograph signal obtained in the preliminary light emission.
1. An electronic camera comprising:
light emission means for emitting a light to an object, said light emission means performing a preliminary light emission and a main light emission;
an imaging element for receiving a light reflected from the object during the preliminary light emission and converting the light into an electrical image signal;
amplifying means for amplifying the electrical image signal; and
setting means for setting a gain for said amplifying means and an amount of light for the main light emission, based on the electrical image signal, said setting means being structured to operate exclusively below a camera shake limitation parameter associated with said electronic camera.
2. The camera according to claim 1 , wherein said setting means increases the gain when the electrical image signal fails to have a desired magnitude even if an amount of the light for the main light emission is set to a maximum.
3. The electronic camera according to claim 1 , further comprising photograph mode selecting means for selecting a desirable one of a plurality of photograph modes, wherein said setting means sets the gain in accordance with the photograph mode selected by said photograph mode selecting means.
4. The electronic camera according to claim 1 , wherein the gain is not changed when a difference or a ratio, in amount between the light reflected from the object during the preliminary light emission, and the light coming from the object when no light is emitted to the object is not more than a predetermined value.
5. The electronic camera according to claim 1 , wherein said setting means generates an alarm when the gain is changed in the main light emission.
6. The electronic camera according to claim 2 , further comprising photograph mode selecting means for selecting a desirable one of a plurality of photograph modes, wherein said setting means sets the gain in accordance with the photograph mode selected by said photograph mode selecting means.
7. The electronic camera according to claim 2 , wherein the gain is not changed when a difference or a ratio, in amount between the light reflected from the object during the preliminary light emission, and the light coming from the object when no light is emitted to the object is not more than a predetermined value.
8. The electronic camera according to claim 2 , wherein said setting means generates an alarm when the gain is changed in the main light emission.
9. The electronic camera according to claim 3 , wherein the gain is not changed when a difference or a ratio, in amount between the light reflected from the object during the preliminary light emission, and the light coming from the object when no light is emitted to the object is not more than a predetermined value.
10. The electronic camera according to claim 3 , wherein said setting means generates an alarm when the gain is changed in the main light emission.
11. The electronic camera according to claim 4 , wherein said setting means generates an alarm when the gain is changed in the main light emission.
12. An electronic camera comprising:
light emission means for emitting a light to an object in present amounts, said light emission means performing a preliminary light emission and a main light emission;
an imaging element for receiving a light reflected from the object during the preliminary light emission and converting the light into an electrical image signal;
amplifying means for amplifying the electrical image signal, with a preset gain;
photograph means for comparing an amount of light received when no light is emitted to the object, which is obtained from the electrical image signal, with a predetermined value to evaluate the amount of light received;
operating means for operating the light emission means when an evaluation result shows that said received light amount is insufficient;
optimum setting value calculating means for obtaining at least one of the main light emission amount and the gain from the amount of the light received when no light is emitted to the object and the amount of the light received during the preliminary light emission; and
setting means for setting at least one of the light emission amount obtained during the main light emission and the gain, as a set value, said setting means being structured to operate exclusively below a camera shake limitation parameter associated with said electronic camera.
13. An electronic camera comprising:
light emission means for emitting a light to an object in present amounts, said light emission means performing a preliminary light emission and a main light emission;
an imaging element for receiving a light reflected from the object during the preliminary light emission and converting the light into an electrical image signal;
amplifying means for amplifying the electrical image signal, with a preset gain;
photograph mode selecting means for selecting a desirable one of a plurality of photograph modes;
photograph means for comparing an amount of light received when no light is emitted to the object, which is obtained from the electrical image signal, with a predetermined value to evaluate the amount of light received;
operating means for operating the light emission means when an evaluation result shows that said received light amount is insufficient;
optimum setting value calculating means for obtaining at least one of the main light emission amount in said selected photograph mode and the gain from the amount of the light received when no light is emitted to the object and the amount of the light received during the preliminary light emission; and
setting means for setting at least one of the light emission amount obtained during the main light emission and the gain, as a set value, said setting means being structured to operate exclusively below a camera shake limitation parameter associated with said electronic camera.
14. The electronic camera according to claim 13 , further comprising emission amount control means for controlling a light emission amount during the preliminary light emission and the main light emission to a set value; and
gain control means for controlling the gain of said amplifying means to a set value.
15. In a method of controlling an electric flash photography performed by an electronic camera comprising light emission means for emitting a light to an object, said light emission means performing a preliminary light emission and a main light emission, an imaging element for receiving a light reflected from the object during the preliminary light emission and converting the light into an electrical image signal, and amplifying means for amplifying the electrical image signal with a preset gain, said method comprising:
selecting a desirable one of a plurality of photographing modes;
comparing an amount of light received when no light is emitted to the object, which is obtained from the electrical image signal, with a predetermined value to evaluate the amount of light received;
operating the light emission means when an evaluation result shows that the received light amount is insufficient;
obtaining at least one of the main light emission amount and the gain from the amount of the light received when no light is emitted to the object and the amount of the light received during the preliminary light emission;
setting at least one of the light emission amount obtained during the main light emission and the gain, as a set value, while maintaining the operation of the electronic camera below a camera shake limitation parameter thereof; and
photographing the object with the main light emission amount set and the gain set.
16. An electronic camera comprising:
a flash portion configured to provide a variable amount of light;
an amplifying portion configured to variably set a sensitivity of a solid-state imaging element;
a mode setting portion configured to be capable of setting a plurality of shooting modes; and
a control portion configured to set an amount of light for a main light emission and a gain in the amplifying portion, based on the reflected light amount from an object and a shooting mode set by the mode setting portion, by making the flash portion perform a preliminary light emission in response to the start of a shooting sequence at a brightness below a camera shake limitation.
17. The electronic camera according to claim 16 , wherein the mode setting portion includes in said plurality of shooting modes an automatic mode, a fixed gain mode and a power-saving mode.
18. The electronic camera according to claim 16 , wherein the control portion issues an alarm when changing the gain in the amplifying portion.