ZOOM LENS, AND OPTICAL EQUIPMENT HAVING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a zoom lens for attaining a wide angle, reducing fluctuation of various aberrations due to variable powers and focusing, and having high optical performance over the whole variable power range and the whole focusing range, while adopting an inner focus system. SOLUTION: This zoom lens has the first and second lens groups of positive and negative refractive powers, and a following lens group of positive refractive power, in this order from an object side, and executes zooming by changing spaces among the respective groups. The following lens group has one or more of lens groups BRX, a lens group BRa of negative refractive power and a lens group BRb of positive refractive power. The lens groups are moved to increase a space between the lens group BRa and the lens group BRb in a tele end with respect to a wide angle end. The focusing is carried out by moving the lens group BRa. The condition of 3.0<¾(1-βBRat2)×βBRbt2¾ is satisfied, whereβBRat represents a lateral magnification in the tele end of the lens group BRa, andβBRbt represents a lateral magnification in the tele end of the lens group BRb. COPYRIGHT: (C)2009,JPO&INPIT