| 摘要 |
PURPOSE: To relieve the tolerance on eccentricity at the time of production and to facilitate production by constituting both of a negative second lens and a positive third lens in a positive first lens group with a tens of a meniscus shape. CONSTITUTION: The first lens group is composed, successively from an object side, a first lens of a positive meniscus shape of which the convex face of a radiusγ1 of curvature is directed to the object side, a second lens of a negative meniscus shape, a third lens of a positive meniscus shape and a fourth lens of a positive lens. Further, a stop is arranged near the fourth lens. Namely, both of the second lens and the third lens are formed to the meniscus shape, by which the incident angle and exit angle of rays are made smaller and the generation of large aberrations at these lens faces are prevented. As a result, the lens system which is less deteriorated in the aberrations with respect to the eccentricity of both lenses and has a good assembling characteristic is obtd.
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