Abstract: A calibration system characterizes luminescence measurement systems, in particular spectrally resolving, wide-field and/or confocal imaging systems. The calibration system has a baseplate with at least one flow-through channel, wherein the at least one channel is formed as a sample chamber for the luminescence measurement system, at least one reservoir in communication with the at least one channel and adapted to receive a liquid, and at least one focusing device integrated into a baseplate for setting a defined measurement beam focus of the luminescence measurement system to be calibrated by using a focusing surface.