1. A system for automatically adjusting a focus setting of an imaging device on an imaging set, the system comprising: one or more tracking markers, each tracking marker comprising an identification means and a tracking pattern, the one or more tracking markers configured for attaching to corresponding one or more subjects to be imaged on the imaging set by the at least one imaging device; a first tracker integrated with the imaging device to gather first image information of the imaging set, the first tracker having a field of view including the one or more subjects; a controller configured for receiving the first image information from the first tracker and for communicating to the imaging device control signals for the adjusting of focus settings for the imaging device based on distances between the imaging device and the one or more subjects; and a database comprising predetermined information about one or more corresponding identities and one or more corresponding tracking patterns of the one or more tracking markers.