| 摘要 |
PURPOSE:To provide a system of a lengthened eye point position by constituting an eyepiece lens of three lense groups, setting the refracting powers and lens shapes of the respective lens groups thereof to specified ones, and moving a part of the lens groups thereof on the finder optical axis thereby adjusting diopter. CONSTITUTION:A focusing plate 1, a condenser lens 2, a block 3 wherein a pentagonal Dach prism is developed, the 1st lens group 4 of a negative refracting power, the 2nd lens group 5 of a negative refracting power, the 3rd lens group 6 of a positive refracting power, and an eye point 7 are provided. The eyepiece lens consists of the 1st lens group 4, the 2nd lens group 5 and the 3rd lens group 6. The eyepiece lens is adjusted of diopter by fixing the groups 4, 6 and moving the group 5 on the finder optical axis. Here, when the focal lengths of the groups 4, 5 are defined as f1, f2, the conditions¦f1¦>¦f2¦are satisfied, whereby the finder optical system of well corrected aberrations is obtained. |
