ZOOM LENS

摘要

PROBLEM TO BE SOLVED: To provide a small wide-angle zoom lens having a variable power ratio larger than three times, sufficiently separating the position of an exit pupil from the image plane, suppressing the distortion aberration and having a small number of lenses and little aberration. SOLUTION: At the time of zooming from the wide-angle end to the telescopic end, a first lens group G1 having a negative refractive power is moved to the image side and reversely moved to the object side on the way, a second lens group G2 having a positive refractive power is monotonously moved to the object side and a third lens group G3 having a positive refractive power is moved to the object side and reversely moved to the image side on the way. An aperture diaphragm S is located on the object side of the second lens group G2 and integrally moved with it. By representing the focal distance of Mth lens group (M=1-3) by fM and the composite focal distance of the whole system at the wide-angle end by fW, the conditions: (1) 2.62<|f1|/fW<2.72 (f1 <0), (2) f3 /fW<3.4 and (3) 0.570, f3 >0) are satisfied.