Optical zoom of the retrofocus type having four lens groups

摘要

Provided is a microminiaturized zoom optical system capable of sufficiently correcting aberration. The zoom optical system (100) includes a first lens group (101) having a negative optical power, a second lens group (102) having a positive optical power, and a third lens group (103) having a positive or negative optical power in this order from the object side. The zoom optical system is configured in such a manner that the interval between the first lens group (101) and the second lens group (102) is decreased in zooming from the wide angle end to the telephoto end. A positive lens element in the third lens group (103) or in a lens group closer to tre image side than the third lens group (103) satisfies the following conditional expression:
ν p<40
where vp is the minimum value of the Abbe number of the positive lens element.