Named after Italian optician Ignazio Porro who patented this image erecting system in 1854 and later refined by makers like Carl Zeiss, binoculars of this type use a double prism Z-shaped configuration to erect the image. This feature results in binoculars that are wide, with objective lenses that are well separated but offset from the eyepiecs.With wider spacing of the objectives, Porro prism designs give better sensation of depth.