1. Camera system for a printing press, such as an offset printing press, which printing press is configured to print a printed image on a substrate, the system comprising a pair of sensor units, the pair comprising a first and second optical sensor unit, each configured to record a respective image of the substrate or the printed image, wherein an angle of view of the first optical sensor unit overlaps an angle of view of the second optical sensor unit in an overlap area and wherein the substrate or the printed image is situated at least partially in said overlap area; a processing unit operatively coupled to said first and second optical sensor units; characterized in that the processing unit is configured to determine a focal distance from at least one of the first and second sensor units to the substrate or printed image using an overlap of the respective images.