| 摘要 |
A real image type variable magnification viewfinder optical system comprising, in order from the object side, an objective lens system having positive refractive power and an eyepiece lens system having positive refractive power. The objective lens system comprises, in order from the object side, a first lens unit having negative refractive power, a second lens unit having positive refractive power, a third lens unit having positive refractive power and a fourth lens unit having positive refractive power. The second lens unit and the third lens unit are moved, with the first lens unit kept fixed, for performing variation of magnification and adjustment of diopter. This viewfinder optical system can have a high magnification and a large field angle of emergence at a low magnification position thereof, a variable magnification ratio of 2 or higher and favorably corrected aberrations, and be manufactured at a low cost.
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