| 摘要 |
PURPOSE:To satisfactorily correct an off-axis meridional image face at a wide angle, by constituting the titled lens with lenses of a first negative group, a second positive group, a third negative group, a fourth positive group, and a fifth negative group, each satisfying a specified condition. CONSTITUTION:The titled lens consists of the first group having a negative refractive power, the second group having a positive refractive power, the third group having a negative refractive power, the fourth group having a positive refractive power, and the fifth group having a negative refracting power, and also, satisfies each condition of the inequalities. In this regard, fw, fI, fII, fIII, and fV denote a focal distance of the whole system at a wide angle side, a focal distance of the first group, a focal distance of the second group, a focal distance of the third group, and a focal distance of the fifth group, respectively. In this way, at the time of executing the zooming extending from the wide angle end to the telephone end, the movement is executed so that an air interval between the first group and the second group, and the third group and the fourth group decreases, and an air interval between the second group and the third group increases, by which the constitution becomes compact so that it becomes a lens constitution of a reverse telephone type at the wide angle side, and a lens constitution of a telephone type at the telephone side, and also, the fifth negative group is placed at the nearest side of an image, by which an out-of-focus meridional image face can be corrected satisfactorily at the wide angle side.
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