| 摘要 |
PURPOSE:To obtain a zoom lens having a zoom ratio of about 8 times, having compact zoom and image formation systems, reducing a small front lens diameter and efficiently correcting aberration by constituting the 1st-5th lens components of specific 15 lenses in 13 groups in total. CONSTITUTION:The zoom lens is formed by arranging 1st-5th lens components successively from the object side so that the 1st lens component is constituted of 3 lenses in 2 groups consisting of a joint lens constituted of a negative meniscus lens L1 turning its convex face to the object side and a positive lens L2 and a positive lens L3, the 2nd lens component is constituted of 3 lenses in 2 groups consisting of a negative lens L4 and a joint lens constituted of a lens L5 having concave faces on both the sides and a positive lens L6 the 3rd lens component is constituted of a negative lens L7, the 4th lens group is constituted of 2 lenses in 2 groups consisting of a positive lens L8 turning its convex face to the image side and a lens L9 having convex faces on both the sides, and the 5th lens component is constituted of a front group consisting of a lens L10 having convex faces on both the sides, a positive lens L11 turning a strong convex face to the object side and a negative lens L12 and having positive refractive force as a whole and a rear group consisting of a negative lens L13 turning its convex face to the image side, a positive lens L14 turning its convex face to the image side and a positive lens L15 turning its convex face to the object side and having positive refractive force as a whole. The zoom lens is satisfied with the conditions shown by inequalities 1.
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