By incorporating a prism pair in an optical system for multiplex holography, the 2-D image for holographic recording can be compressed in one direction with respect to the other direction. Hence, a cylindrical lens with smaller aperture can be used. The effects of the prism pair on the image of the original object and on the real image of the illuminating source point are analyzed. The aspect ratio of the image for hologram recording can be continuously varied with the least root mean square error of the object. Experimental results confirming the results of computer simulation are also provided.