These are extremely light/compact binoculars perhaps designed to fit inside a woman's purse. The design is unique in that the eye distance is achieved by double hinge design. A single hinge can not extend far enough form a compact to wide open to the human eye distance. This makes the design challenging but as optomechanics dictates a variety of options, the most user friendly Zeiss has come up with is to place the diopter adjustment behind one hinge, and the focusing knob on the other. I have disassembled a similar design (Leica) with similar optomechanical layout. In Leica, the designer decided to place both knobs on the right hinge, one in front, and one on the back.
