| 摘要 |
PROBLEM TO BE SOLVED: To provide a lens system in a distance-measuring apparatus which can be switched to a wide and a telescopic modes, in which a lens is thin, a distance-measuring lens system occupies a small volume and a projection angle is variable. SOLUTION: The distance-measuring apparatus comprises a light-emitting means, a light projection lens system for projecting light emitted from the light-emitting means to an object to be photographed, a light-receiving lens system for condensing light reflected by the object to be photographed, and a detecting means for detecting the reflected light. The light projection lens system or light-receiving lens system is obtained by adding a converter lens CL to a master lens ML thereby to change a focal length. The master lens ML or converter lens CL has a diffraction type optical element both faces of which are plane, at least one of which is a plane of diffraction. |
