A method for investigating one or a plurality of phase objects is described, in which a grid made up of elements is used, which is illuminated with light of a light source, the coherence length of which is larger than the average spacing of adjacent elements of the grid. A diffraction image of the illuminating light scattered on the grid is generated, whereby the one or the plurality of phase objects are placed in the light path between the light source and the grid and/or in the light path of the illuminating light scattered on the grid. At least a part of the diffraction image is detected by an optical sensor directly or after interaction with further optical components and converted into a signal. The signal is analyzed further in order to ascertain information relating to the one or plurality of phase objects therefrom. A corresponding device is likewise described.