the present invention relates to a small zoom lens system for electronic still cameras or video cameras , which has a zoom ratio lying in the range of about 2 . 5 - 3 . 2 and an f - number lying in the range of about 2 - 2 . 8 , comprises as small as 7 or 8 lenses and is reduced in terms of both the total length and the lens diameter , and which is characterized by comprising , in order from the object side , at least a first lens group having a positive refractive power , a second lens group having a negative refractive power , a stop and a third lens group having a positive refractive power , and in that during zooming the first lens group remains fixed while the second and third lens groups are moved along the optical axis , and the following conditions and are satisfied : 0 . 9 × β . sub . 2t / β . sub . 2w & lt ; β . sub . 3t / β . sub . 3w & lt ; 2 . 0 × β 2t / β 2w , , and 0 . 5 & lt ; f . sub . 3 /| f . sub . 2 |& lt ; 1 . 5 , where β 2t is the magnification of the second lens group at the telephoto end , β 2w is the magnification of the second lens group at the wide angle end , β 3t is the magnification of the third lens group at the telephoto end , β 3w is the magnification of the third lens group at the wide angle end , f 2 is the focal length of the second lens group , and f 3 is the focal length of the third lens group .