| 摘要 |
PROBLEM TO BE SOLVED: To provide a small-sized zoom lens having a small decrease of a zoom ratio in close-up imaging, a high zoom ratio, and high optical performance over the whole zoom range.SOLUTION: A zoom lens comprises as lens groups sequentially from an object side to an image side: a first lens group U1 having positive refractive power; a second lens group U2 having negative refractive power; a third lens group U3 having negative refractive power; a fourth lens group U4 having positive refractive power; and a fifth lens group U5 having positive refractive power. Upon focusing, the fourth lens group moves. A lateral magnification β2t of the second lens group at the telephoto end, a lateral magnification β3t of the third lens group at a telephoto end, a lateral magnification β4w of the fourth lens group at the wide angle end, and a lateral magnification β4t of the fourth lens group at the telephoto end satisfy both of -1.4<β2t×β3t<-0.4 and 1.02<β4w×β4t.SELECTED DRAWING: Figure 1 |
