In a method and magnetic resonance (MR) apparatus for creating a common updating kernel for at least two datasets, a first dataset is acquired from a subject that includes Nyquist undersampled measurement data acquired from at least two reception coils of an MR scanner, and that also includes calibration data. At least one further dataset is acquired, that contains Nyquist undersampled measurement data acquired with said coils, and also includes calibration data. A common calibration dataset is created from the calibration data in the first and the at least one further dataset. An updated first dataset and at least one updated further dataset are determined using the common calibration dataset. A combination image dataset can be produced from these updated datasets.