Apparatus for detecting focusing state of objective lens

A camera system comprising:

• an imaging lens assembly removably mounted on a camera body and having a focusing lens unit including focusing lens means for forming an object image and information storage means for storing defocus information on a maximum defocus amount;
• said camera body including light intensity distribution forming means for forming light intensity distributions concerning images whose relative positional relationship changes in accordance with a focusing state of the focusing lens means, sensing means having a plurality of sensors for sensing the light intensity distributions to produce first and second signals relating to the light distributions, signal processing means for relatively displacing the first and second signals by determining correlation information and producing a signal for adjusting the focusing state of said focusing lens means in accordance with said correlation information, and altering means for altering a displacement range within which said first and second signals are relatively displaced in accordance with defocus information stored in said information storage means.