Zoom lens employing lens eccentricity approach to compensate for image blur due to hand tremor

摘要

Zoom lens, using lens eccentricity to compensate for image blur, has four groups of lens pieces; 1^st, 3^rd and 4^th, each with positive refractive power, and 2^nd with negative refractive power, arranged in series on “closer to a subject first” basis. Moving from wide to telephoto causes 1^st and 2^nd groups to separate from each other, 2^nd and 3^rd groups to come closer to each other, and 3^rd and 4^th groups to come closer to each other. The leading subset of the 4^th group is closest to the subject, includes lens elements of positive and negative refractive power cemented together, and serves as an anti-tremor shift lens. The zoom lens satisfies the follows:1.45f41/fw1.8where f41 is a focal length of the leading subset in the 4th lens group, and fw is a focal length of the lens optics as a whole in the wide-angle mode.