Patent ID: 7460779

Claim:
A focus detection system comprising: at least one line sensor array having a plurality of areas, each of which includes a plurality of pixels, wherein said line sensor array photoelectrically converts object light received by each of said plurality of pixels into electric charge to accumulate said electric charge, and outputs said accumulated electric charge as an image signal; a plurality of monitor sensor arrays, positioned so as to be adjacent to said plurality of areas of said line sensor array, for monitoring amounts of light received by said plurality of areas of said line sensor array to output monitor signals representing said amounts of light, respectively; a controller which terminates an integral operation of said line sensor array immediately after said monitor signals reach an integration termination value; and a saturation detecting device for detecting whether said image signal reaches a predetermined level of saturation, wherein, in the case where said saturation detecting device detects that said image signal reaches said predetermined level of saturation, said controller changes said integration termination value so that said monitor signals reach said integration termination value in less time, and makes said line sensor array perform said integral operation again.