Abstract: The range binoculars include first and second observing optical systems, a laser beam-emitter for emitting a laser beam, a measuring optical system for collimating the laser beam and sending the collimated laser beam to a target. A laser beam-receiving device receives the laser beam reflected by the target, while a distance-determining device determines the distance between the observation place and the target from the flight time of the laser beam taken from the laser beam-emitter to the laser beam-receiver. A measurement-displaying device displays the measurements obtained by the distance-determining device.

Abstract: A pair of variable-powered binoculars include a pair of objective lens systems; a pair of prism systems, each of the prism system inverting an image that advances through the corresponding objective lens systems, from an inverted image to an erecting image; a pair of concave adjusting lenses, each of the concave adjusting lenses placed between a focus formed by the corresponding objective lens system and the corresponding prism system, so that each of the concave adjusting lenses is movable along the optical axis formed by the corresponding objective lens system and the corresponding prism system; and a pair of ocular lens systems, each of the ocular lens systems placed on the optical axis, so that each ocular lens system is movable along the optical axis closer to or away from the corresponding concave adjusting lens, synchronizing with a movement of the corresponding concave adjusting lens.

Abstract: The invention relates to improving optical properties of optical instruments with variable magnification, such as zoom binoculars, reducing the weight thereof, and enabling the user to change magnifications quickly. The invention provides an optical instrument with a focal length-varying lens 4 disposed on the optical axis between an objective lens 7 and an eyepiece 3, further having an adjusting lens 5 for adjusting optical properties when the focal length-varying lens is in an area to provide high magnification. The adjusting lens is supported so that it is capable of moving between a location on the optical axis and a location off the path of light beams. Interlocked with a magnification-varying mechanism that controls the position of the focal length-varying lens, the adjusting lens is moved to the on-the-axis location when the focal length-varying lens is in an area to provide high magnification, and to the off-the-axis location when low magnification.