| 摘要 |
A real image mode variable magnification finder optical system has a finder objective for forming an optical path different from a photographic objective, an image erecting optical member for erecting an image formed by the finder objective, and an eyepiece having a positive refracting power. The finder objective includes the first lens unit having a negative refracting power, the second lens unit having a positive refracting power, the third lens unit having a negative refracting power, and the fourth lens unit having a negative refracting power, so that the second lens unit and said third lens unit are movable along the optical axis to change spaces among respective lens units from the first lens unit to the fourth lens unit. In this way, the finder optical system is obtained which bears a high variable magnification ratio, but is compact in size and provides good correction for aberration.
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