Interferometric imaging systems measure the complex visibility, which is the Fourier transform of the source brightness distribution, according to the van Cittert-Zernike theorem. Both the amplitude and phase of the visibility are needed to produce images of a complex object structure by Fourier inversion. In this paper, by using the generalized imaging theory of a diffraction-limited incoherent imaging system, the pinhole model and the circular aperture model of the interferometry are presented and derived. The approximate condition, which should be followed by optical aperture synthesis imaging interferometry, is obtained by comparing two models. Based on this condition, the angle of field-of-view (FOV) in the object space is analyzed and determined. At the good approximation, the FOV is about one-sixth of an Airy disk of an elementary aperture diffraction. Also the computer simulation results are presented and match the theoretical results very well. This suggests that the extremely high image resolution can be achieved in the interferometric imaging systems, but it generally has a very small field of view. Such imaging systems are suitable only for the astronomical application.