The invention relates to a camera system (1) for a vehicle (2). The camera system (1) is configured to acquire image data of a surrounding of the vehicle (2) and comprises a camera (10) and a control module (20). The control module (20) is configured to determine, whether a calibration of an intrinsic parameter of the camera system (1) is required, by determining an error in a back projection, a forward projection and/or a reprojection of the image data and by determining whether the error exceeds a predefined threshold.