Patent attributes
A portable camera-phone has a strobe consisting of LEDs emitting light with a determined quantity of light emission, as an auxiliary light source for image pick-up of an object by a camera. In an image pick-up mode, the light emission quantity is adjusted repeatedly until a total exposure value matches an optimal exposure value, based on a difference between a total exposure value of an image signal output from the camera with the light emission quantity determined last time and a total exposure value when emission is OFF. Therefore, in the image pick-up mode, two reference values are used for determining the light emission quantity to have the total exposure value match the optimal exposure value, and hence the light emission quantity can be determined with high accuracy. As a result, an optimal exposure level can be obtained with high accuracy.