A variable power optical
system includes, in order from the object side, a first lens group having negative refractive power, a variable
power group having positive refractive power, and a final lens group having positive refractive power. The variable
power group is provided with, in order from the object side, a first lens element having positive refractive power, a second lens element, and a third lens element. The second lens element has a convex shape on the object side. The final lens group includes a positive lens. The variable power optical
system satisfies the following conditions:10≦VdLg≦45−1.0<(R2a−R2b) / (R2a+R2b)<1.0where VdLg is the
Abbe number of the positive lens of the final lens group with respect to the d line, R2a is the curvature
radius of the object-side surface of the second lens element, and R2b is the curvature
radius of the image-side surface of the third lens element.