| 摘要 |
PROBLEM TO BE SOLVED: To obtain a zoom lens which is small in size and is well corrected in chromatic aberration as a zoom lens for compact camera having a variable magnification ratio of about 4. SOLUTION: This zoom lens has at least three lens groups including, in order from an object side, a first lens group 1G having positive refracting power, a second lens group 2G having positive refracting power and a third lens group 3G having negative refracting power. All of these three lens groups move to the object side at the time of zooming from a short focal length side to a long focal length side. The first lens group 1G is composed, in order from the object side, three elements; a negative first lens, a positive second lens and a positive third lens and satisfies the following conditional equations I to IV. (I) 4.3<m3 T<6, (II) 1.7<fT/f1 G<3, (III) 31<ν1 <55, (IV) 0<ν2 -ν1 <30, where m3 T is the transverse magnification of the third lens group at the long focal length end; fT is the focal length of the entire system at the long focal length end; f1 G is the focal length of the first lens groups;ν1 is the Abbe number of the negative first lens in the first lens group;ν2 is the Abbe number of the positive second lens in the first lens group.
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