| 摘要 |
PURPOSE:To execute focusing by providing a mirror for bending a luminous flux, and making a luminous flux image passing through a semi-transparent part of a luminous flux dividing device 1 conform with a luminous flux image passing through its outside. CONSTITUTION:Lenses 301, 302, 303 and 304 are a lens system to an afocal part of a zoom lens, and a luminous flux dividing device I 305 divides and reflects the greater part of an incident luminous flux at a right angle with the optical axis direction, and forms an image on a focal face 307 by a lens 306. A luminous flux which is divided and made to pass through in the optical axis direction by the luminous flux dividing device I 305 enters into a finder system. A luminous flux dividing device II 308 is used for focusing, a concave lens 309 forms an objective lens of the finder, and constitutes a reverse-Galilean finder system together with a convex lens 310 which becomes a rear eyepiece, and 312 becomes a position of the pupil. As for the lenses 301-304, the lens diameter is made large so that a luminous flux which is brighter than F- number required for photographing passes through, and passes through the transparent part of the luminous flux dividing device I 305, and the luminous flux is bent so as to fall at right angles with the optical axis by reflectors 311a, 311b, and is made to conform with an image of the luminous flux passing through the oblique line part of the luminous flux dividing device I 305, by which focusing can be executed. |
