Patent ID: 7471334

Claim:
A method of operating a digital camera selectively in a picture-taking mode for taking pictures of a subject, a sleep mode for conserving energy, and a test mode for presetting an exposure setting, the method comprising: appreciably reducing power consumption of the digital camera by switching to the sleep mode; periodically updating the exposure setting to a preliminary exposure setting by periodically switching from the sleep mode to the test mode in response to a clock signal, wherein the preliminary exposure setting is at least partially based on an amount of light sensed by the digital camera during the test mode; switching from the sleep mode to the picture-taking mode in response to the digital camera detecting that the subject is present; while in the picture-taking mode, taking a first picture of the subject with the exposure setting at the preliminary exposure setting if the preliminary exposure setting is at a predetermined appropriate value for the first picture; while in the picture-taking mode, adjusting the exposure setting to a more appropriate exposure setting if the preliminary exposure setting is decidedly inappropriate for the first picture; and taking a second picture of the subject with the exposure setting at the more appropriate exposure setting if the preliminary exposure setting is decidedly inappropriate value for the first picture.