Digital camera and exposure control method
Shutter blades are driven so that light which hits an image sensor which has been hit by the light is blocked (timing t 5 ). That the shutter blades have moved a predetermined amount is detected before the start of the shutter blades blocking the light (timing t 6 ), and furthermore, reset scanning of the exposure amount of the image sensor vertically upwards is started at a reset timing according to the detection before the start of the shutter blades blocking the light (timing t 7 ). Due to this, it is possible for the exposure amount of the image sensor to be reset at a timing corresponding to the type of driving of the shutter for each camera in a case where there is variation or change in the type of driving due to individual unit differences or changes over time in the shutter mechanism.
1. A digital camera comprising:
an image sensor which generates an image signal based on an exposure amount;
a shutter which blocks light which hits the image sensor by moving in a predetermined direction;
a movement control section which moves the shutter so that light which hits the image sensor is blocked;
a movement detection section which detects that the shutter has moved a predetermined amount from the start of the movement after the start of the movement of the shutter and before the start of the shutter blocking the light which hits the image sensor;
an exposure time section which receives an exposure time which is for the image sensor to be exposed; and
a reset control section which starts reset scanning of the exposure amount of the image sensor in the predetermined direction at a timing according to detection by the movement detection section before the start of the shutter blocking the light which hits the image sensor in a case where the exposure time is shorter than a time threshold which is determined in advance and starts reset scanning of the exposure amount of the image sensor in the predetermined direction with no relation to detection, after the start of the movement of the shutter, by the movement detection section so that the image sensor is exposed during the exposure time in a case where the exposure time is longer than the time threshold which is determined in advance.
2. The digital camera according to claim 1 ,
wherein the time threshold is a time which is determined in advance to be within the time which is necessary for the movement of the shutter from the predetermined amount of movement after the start of the movement of the shutter to the start of the blocking of the light which hits the image sensor.
3. The digital camera according to claim 1 ,
wherein, in a case where the exposure time is shorter than the time threshold, the reset control section starts the reset scanning of the exposure amount of the image sensor in the predetermined direction at a timing which is earlier in a case where the exposure time is longer than a predetermined exposure time compared to a case where the exposure time is shorter than the predetermined exposure time and which is later in a case where the necessary detection time is longer than a predetermined required time compared to a case where the necessary detection time is shorter than the predetermined required time.
4. The digital camera according to claim 1 ,
wherein the reset control section starts the reset scanning of the exposure amount of the image sensor in the predetermined direction at a timing according to detection by the movement detection section after the start of the movement of the shutter and the previous detection by the movement detection section after the start of the movement of the shutter in a case where the exposure time is shorter than the time threshold and starts the reset scanning of the exposure amount of the image sensor in the predetermined direction at a timing not according to detection by the movement detection section after the start of the movement of the shutter and according to the previous detection by the movement detection section after the start of the movement of the shutter in a case where the exposure time is longer than the time threshold.
5. The digital camera according to claim 1 ,
wherein the movement detection section detects a detection position, which is between an edge portion on the image sensor side in an open state of the shutter and an edge portion of the image sensor on the shutter side, being reached by the movement of the shutter in a case of imaging in the optical axial direction.
6. The digital camera according to claim 1 ,
wherein the movement detection section detects the movement of the shutter by detecting an action of a connection member which is connected to the movement of the shutter.
7. An exposure method of a digital camera, which is provided with an image sensor which generates an image signal based on an exposure amount and a shutter which blocks light which hits the image sensor by moving in a predetermined direction, comprising:
(a) starting movement of the shutter so that light which hits the image sensor is blocked;
(b) detecting that the shutter has moved a predetermined amount from the start of the movement after the start of the movement of the shutter and before the start of the shutter blocking the light which hits the image sensor;
(c) receiving exposure time which is for the image sensor to be exposed;
(d) starting reset scanning of the exposure amount of the image sensor in the predetermined direction at a timing according to the detection in (b) which is after the start of the movement of the shutter before the start of the shutter blocking the light which hits the image sensor in a case where the exposure time is shorter than a time threshold which is determined in advance; and
(e) starting reset scanning of the exposure amount of the image sensor in the predetermined direction with no relation to detection, after the start of the movement of the shutter, in (b) so that the image sensor is exposed during the exposure time in a case where the exposure time is longer than the time threshold which is determined in advance.