IMAGING OPTICAL SYSTEM AND ELECTRONIC IMAGING DEVICE HAVING IT

摘要

PROBLEM TO BE SOLVED: To provide a zoom lens for miniaturizing and thinning by lessening the number of the constituents of an optical system, and to provide an electronic imaging device having it. SOLUTION: The imaging optical system has a positive lens group, a negative lens group, and a diaphragm. The optical system arranges the positive lens group at an image face side from the diaphragm. The positive lens group has a cemented lens cementing a plurality of lenses. When a straight line expressed by Nd=α×νd+β(where,α=-0.004) is set in an orthogonal coordinate system making Nd of a horizontal axis and makingνd of a vertical axis, Nd andνd of at least one lens constituting the cemented lens are included in both a region decided by straight lines at a lower limit and upper limit of the following condition inequality (1) and a region determined by the following condition inequalities (2) and (3). 1.40<β<1.72... (1), 1.30