| 摘要 |
A Keplerian zoom finder system has sequentially from its object side an objective lens with positive refractive power, a field lens with positive refractive power arranged in the vicinity of the focus of the objective lens, and an ocular with positive refractive power for observing the object image by the objective lens in enlargement. In the finder system, the aforesaid objective lens has from its object side the first lens of a biconcave lens with a more enhanced concavity toward the object side and the second lens of a biconvex lens with an aspherical surface on the eye point side. The Keplerian zoom finder system thus structured is characterized in that its finder magnification is varied by varying the air spacing between the aforesaid first lens and second lens and the conditions are satisfied.
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