| 摘要 |
A real image mode zoom finder includes, in order from the object side, an objective optical system with positive refracting power having a first lens unit with negative refracting power, a second lens unit with positive refracting power, a third lens unit with positive refracting power, and a fourth lens unit with negative refracting power; an image erecting system for erecting an intermediate image formed by the objective optical system; and an ocular optical system with positive refracting power. In this case, each of lens units constituting the objective optical system is constructed with a single lens, and the object-side surface of the first lens unit is configured to be concave. Moreover, the objective optical system satisfies the following condition:2.5< alpha T(R2)<5.7where alpha T(R2) is a combined longitudinal magnification ranging from the second lens unit of the objective optical system to the intermediate image at the telephoto position of the finder.
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