| 摘要 |
A large aperture long focus macro lens system comprising a first lens group having positive refractive power, a stop, a second lens group having positive refractive power, and a third lens group in the order from the object side, the large aperture long focus marco lens system being arranged to be focused on an object at a short distance by advancing the lens system as a whole in the state that the first lens group, the stop and the second lens group are advanced integrally by varying the relative airspace in respect to the third lens group, the large aperture long focus macro lens system being arranged that aberrations are corrected favorably and the variation of aberrations at the time of focusing is small and that the working distance does not become short and the advancing amount of the lens system does not become large when focused on the object at a very short distance.
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