| 摘要 |
PURPOSE:To eliminate a ghost image, and to make the effective diameter small by using the surface of an object side of one lens having a positive refracting power, as the reflecting surface of an Albada system, and specifying a relation of the overall length of a finder and thickness on an axis of the lens. CONSTITUTION:The titled finder has an objective lens group of a negative refracting power, and an eyepiece group of a positive refracting power in order from an object side, and the surface of the object side of one lens having a positive refracting power becomes the reflecting surface of an Albada system. Also, when L: d1: and (m) denote the overall length of the finder, thickness on the axis of the i-th lens from the object side in the eyepiece group, and the number of pieces of constitution lenses, respectively, each condition of the expression is satisfied. In such a way, the finder is miniature, and with regard to both the finder system and the Albada system, the aberration is corrected satisfactorily, and the generation of a ghost image can also be suppressed.
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