The purpose is to provide a large-aperture-ratio internal focusing
telephoto lens applicable to a wider photographing area by equipping a
vibration reduction function capable to satisfactorily correct a camera
shake and the like with securing superb optical performance. The
large-aperture-ratio internal focusing telephoto lens includes, in order
from an object, a first lens group G1 having positive refractive power, a
second lens group G2 having negative refractive power, and a third lens
group G3 having positive refractive power. The second lens group G2 is
moved along an optical axis upon changing focus from infinity to a
close-range object. The first lens group G1 has at least two cemented
lenses and satisfies a given conditional expression. Either one of the
cemented lens satisfies a given conditional expression.