ZOOM LENS, AN OPTICAL INSTRUMENT, AND A MANUFACTURING METHOD FOR A ZOOM LENS WITH THE 7 TIMES OF MAGNIFICATION RATIO

摘要

PURPOSE: A zoom lens, an optical instrument, and a manufacturing method for a zoom lens are provided to implement an excellent optical performance by favorably revising an aberration in each focal distance state from an optical sensing state to a telescopic state. ;CONSTITUTION: A zoom lens(ZL) comprises a first lens group, a second lens group, a third lens group, and a fourth lens group(G4). The first lens group and the third lens group have a positive refractive power. The second lens group and the fourth lens group have a negative refractive power. The first lens group has a negative meniscus lens(L11) and a positive meniscus lens. The second croup lens has a negative meniscus lens, a biconcave shaped negative lens, and a positive meniscus lens(L23). The fourth group lens has a piece of the positive lens(L41). The negative refractive power of three pieces of lens is bigger than 1.9 of that of the zoom lens.;COPYRIGHT KIPO 2011