The invention relates to a
macro-
zoom optical
system, in particular to a
macro-lens with an inner focusing structure. The
macro-
zoom optical
system sequentially comprises a first lens group with positive focal power, a second lens group with negative focal power, a third lens group with positive focal power, a fourth lens group with positive focal power, and a light receiving surface from the object side to the image side; the first lens group and the third lens group are fixed groups, the second lens group is a
zoom group, and the fourth lens group is a focusing group; the second lens group is moved back and forth along the
optical axis direction so as to realize zoom from the wide angle end to the
telescope end; the fourth lens group is moved towards the object side along the optic axisdirection, so as to correct the
soft focus due to zooming process and change of
object distance. The macro-zoom optical
system has the advantages that the glass with extra low dispersion is not contained, the weight is light, the size is small, the F value is constant in the zoom process from the wide angle end to the
telescope end, and various aberrations can be well compensated in the whole-focus range.