Patent ID: 6813092
Filing Date: 2004-11-02
Classification: G02B

Abstract:
A zoom lens apparatus, comprising:a variable-magnification lens which is held by a first lens frame and movable along an optical axis in a lens barrel; and a correcting lens which is held by a second lens frame and movable along the optical axis in the lens barrel, wherein: the variable-magnification lens is shifted so as to vary a focal distance of the zoom lens, and the correcting lens is shifted so as to compensate for any focus blurring due to the shifting of the variable-magnification lens; at least one of the first and second lens frames comprises: an inner frame which holds the lens; an outer frame which holds the inner frame to be shiftable back and forth along the optical axis; and a drive device which shifts the inner frame back and forth relative to the outer frame; and any focus blurring due to variations in wavelength of subject light is compensated for by causing the drive device to shift the inner frame relative to the outer frame and thereby shifting at least one of the variable-magnification lens and the correcting lens.