Abstract: An improvement in zoom binoculars is disclosed which utilizes a small gear rotated by a larger drive gear connected to a pivotally mounted lever for transmitting rotation to one of two intermediate gears which are meshed to each other through free central gear. Each intermediate gear is meshed with a tube gear connected to a tube lens. Each intermediate gear with its meshed tube gear is rotatably mounted on one of a pair of binocular body portions which are pivotally mounted to each other. The pivotally mounted body portions can be pivoted with respect to each other to change the spacing between lens tubes. Due to the small size of the small gear, such pivoting of the body portions produces only a small differential rotation between the two intermediate gears, and thus a small differential and magnification throughout the entire range of magnification for the zoom binoculars.