Abstract: Described is a method for interferometric measurement in which a monochromatic, coherent and parallel, convergent or divergent radiation is directed onto the test object so as to generate in a manner of an interference fringe pattern, the distances between two adjacent fringes being correlated to .lambda./2 distances in the object space.The radiation reflected from the object and containing an interference field, giving rise to said fringe pattern, is redirected onto the test object, e.g. by a suitable mirror arrangement under an angle of incidence different from the angle of incidence of the radiation first impinging on the test object.This radiation, after reflexion from the test object, forms an interference field comprising four interfering components and producing, e.g. on an observation screen, an interference fringe field. By properly adjusting the angles of incidence of both radiations, the distances between adjacent fringes can be made to correspond to .lambda./4 distances in the object space.