Figure 1: Principle of Fizeau and Michelson configurations for a large multi-element interferometer (A,B). A is equivalent to Michelson's periscopic train, while zoom lenses Z on each beam of the telescope-like array B provide adjustable conversion from Fizeau to Michelson geometries. The zoom lenses are assumed to preserve the image focus while changing the image scale. They can be adjusted from a neutral position, providing the 1x image magnification corresponding to the Fizeau geometry (C), towards increasingly demagnified images providing Michelson's wider sub-pupils (D). The variable focal ratio in the sub-images leaves the array's global focal ratio 1/ nearly invariant, thus not affecting the scale of the fine interference structure. When zooming however, the image's Airy envelope varies in size since it is the diffraction pattern of the sub-apertures.