Light level detecting and indicating method for image photographing and recording

Abstract

A light level detecting method uses an automatic gain control of an electrically transformed image signal, thereby obviating the need for a separate light sensor. Instead, the method makes use of the image signal in the recording process. The light detecting and indicating method includes the steps of: (a) setting up a reference value corresponding to an amount of light which requires an automatic gain control; (b) measuring the amount of light of an optical input signal; (c) calculating a comparative value corresponding to the amount of light, where the comparative value controls the performance of the automatic gain control; (d) comparing the reference value with the comparative value; and (e) determining that the amount of light is insufficient when the result of the comparing step falls within a predetermined gain control range.

Dependencies are inferred from the claim text.