| 摘要 |
PROBLEM TO BE SOLVED: To provide a real image variable magnification finder which is less affected by variations of humidity and temperature though being low-cost and is suitable for, especially, about 1.7 variable power ratio of finder magnifications and to provide an image pickup device using the same. SOLUTION: The real image variable magnification finder has; an objective optical system 1 which forms an intermediate image of an object and has a positive refracting power; a visual field frame 4 in the vicinity of an intermediate image position; an eyepiece optical system 5 which forms a pupil for observing the intermediate image and has a positive refracting power; and an erect normal image optical surface for deflecting an optical path to make an erect normal image. The objective optical system 1 has a negative simple lens L11 and a positive simple lens L12 and is moved while changing the gap between the lenses when varying a power. The eyepiece optical system 5 has a prism P51 having an incidence surface in the vicinity of the intermediate image position and a positive simple lens L52. An erect normal image optical surface is divided and arranged before and after the intermediate image position. The total number of lenses and prism having refracting powers is 4, and they are made of plastics. COPYRIGHT: (C)2005,JPO&NCIPI
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