| 摘要 |
PROBLEM TO BE SOLVED: To obtain a zoom lens where various kinds of aberration are satisfactorily corrected so as to be satisfactorily used for a high pixel digital camera while the lens is provided with the high variable power of 5 to 11 and the lens has a wide half viewing angle of 40 deg.. SOLUTION: The zoom lens consists of a 1st lens group 1G whose refractive power is positive, a 2nd lens group 2G whose refractive power is negative and a 3rd lens group 3G whose refractive power is positive in order from the object side, and at least the 2nd lens group is moved and the 3rd lens group is moved to the object side so that a distance between the 1st lens group and the 2nd lens group may be increased and also a distance between the 2nd lens group and the 3rd lens group may be reduced in the case of varying the power from a short focal end to a long focal end, and the 1st lens group includes at least one negative lens and one positive lens, and it satisfies the following conditional inequalities; 4.5<f1/fW<20 and 2.9<β3T/β3W<8, provided that the focal distance of the 1st lens group is expressed by f1, the focal distance of the zoom lens at the short focal end is expressed by fW, and the paraxial horizontal power of the 3rd lens group at the short focal end and at the long focal end are expressed byδ3W andδ3T, respectively.
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