| 摘要 |
An eyepiece which has a simple lens group construction of a relatively small number of lenses and which is reduced in aberration and increased in field angle. The eyepiece includes, as arranged in the order from an eyepoint side, a first lens group of a positive refractive power composed of a cemented lens of a negative lens and a positive lens, and a second lens group of a positive refractive power composed of a single positive lens. With the positive lens of the second lens group, at least one of the lens surfaces is an aspherical surface. With f representing the focal length of the eyepiece, f1 the focal length of the first lens group, and D the spacing between the first and second lens groups, the eyepiece satisfies the following conditions.1.05 f1/f<2.5D/f<0.9
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