The evolution of bubble domains in a (Co/Pd)80 multi-layered thin film with perpendicular anisotropy has been studied by Magnetic Force Microscopy in varying magnetic fields. As expected, the bubble domains show a continuous increase of their size with decreasing field. The diameters have been quantitatively evaluated by means of signal deconvolution. To that end the MFM tip was previously calibrated on the same multilayer in zero field state. The resulting bubble diameters and the values for bubble strip-out and collapse fields agree well with the theoretically predicted values for this system, proving the validity of the applied micromagnetic model.