A microscope, method and computer program for obtaining quantitative phase images by digital holographic microscopy. The microscope includes: a coherent light source (1) and a beam splitter (3) for generating an object beam (Lo) for illuminating a sample, and a reference beam (Lr); an optical system with a main optical path making up a telecentric afocal system, and a reference optical path; and recording means (12) recording a hologram of said sample in the image plane of the optical system. The method includes recording a hologram in the image plane of an optical telecentric afocal system. The computer program is adapted for implementing part of the steps of the method.