| 摘要 |
An Albada finder has a negative objective lens and a positive eyepiece lens. A frame is formed inside the area of the object-side surface of the positive eyepiece lens and a partial reflection area is formed on the eyepiece-side surface of the negative objective lens. The partial reflection area reflects an image of the frame. The frame is formed to enclose a small area of the object-side surface of the eyepiece lens while the partial reflection area is formed to enclose a small area of the eyepiece-side surface of the objective lens. Substantially all of the remaining area of the eyepiece-side surface of the negative objective lens not enclosed by the partial reflection area fully transmits all light incident on the surface.
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