each of the embodiments above an aspheric surface is used for the object side lens surface of the second negative meniscus lens l2 but an aspheric lens surface can be used in the first negative meniscus lens l1 or in both the first negative meniscus lens l1 and the second negative meniscus lens l2 alternatively an aspheric lens surface can be used in the positive lens l3 in the first lens unit g1 or in a lens in the second lens unit g2 in addition to the first negative meniscus lens l1 and the second negative meniscus lens l2 furthermore in each of the embodiments above an aperture stop a is provided between the positive lens l4 and the positive lens l5 in the second lens unit g2 but the aperture stop can be placed between the first lens unit g1 and the second lens unit g2 or behind the second lens unit g2 moreover in each of the embodiments above a flare stop s is provided toward the back of the second lens group g2 in order to reduce coma also the upper flare stop s is given a different locus of motion from the second lens unit g2 but the flare stop s can be given any locus of motion as long as coma is reduced by shielding by the flare stop moreover even if.