| 摘要 |
PROBLEM TO BE SOLVED: To make a camera using a zoom lens small in size, especially, in the depth direction by arranging a mirror folding an optical axis between lens groups moving in the case of zooming. SOLUTION: This zoom lens system is constituted of a positive 1st lens group 10, a negative 2nd lens group 20 and a positive 3rd lens group 30 in order from an object side, and the mirror M is arranged between the 2nd and the 3rd lens groups 20 and 30. Zooming is performed by moving the 2nd and the 3rd lens groups 20 and 30 in an optical axis direction. That is, the 2nd and the 3rd lens groups 20 and 30 are movable variable power lens groups. The mirror M is arranged between the movable variable power lens groups 20 and 30, that is, the lens groups moving together in the case of zooming so as to fold the optical axis by 90 deg.. The mirror M is immovable. Then, an imaging device 50 is arranged on an image-formation surface through a cover glass CG. Thus, the miniaturization of the camera, especially, in the depth direction is advantageously realized.
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