| 摘要 |
PURPOSE: To obtain a large aperture telephoto macrolens which is corrected in aberration in all states from infinity to a close range of a high magnification of about 1/2 times, is relatively compact and has good operability. CONSTITUTION: This lens has a first group G1 having positive refracting power, a second group G2 having negative refracting power, a third group G3 having positive refracting power and a fourth group G4 having negative refracting power and is so constituted that the second group G2 moves to the image plane side and that the third group G3 moves to the object side at the time of focusing from an infinite object to a close range object. The second group G2 which is the moving group is composed to include at least one of a negative meniscus lens of which the concave face is directed to the object side and combined negative lens which is composed of a positive lens and a negative lens and of which the joint face has positive refracting power. The lens is so composed as to satisfy 1.1<β4 <1.4 when the lateral magnification in the state of focusing to the infinity of the fourth group G4 is defined asβ4 .
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