The invention relates to a small-format yet high-performance two units or
three units type zoom lens with a negative unit at the front, which has a
zoom ratio of about 3, an angle of view of as wide as 60.degree. at the
wide-angle end and high image-formation capability, and is much less
susceptible to chromatic blurring, with a compact lens barrel. The zoom
lens comprises a first lens unit G1 of negative refracting power and a
second lens unit G2 of positive power, wherein zooming is implemented by
varying the space between the lens units. The first lens unit G1 is made
up of one negative lens L.sub.11 and one positive lens L.sub.12, two in
all, and satisfies specific conditions with respect to their refractive
index and Abbe constant.