Zoom lens system

A zoom lens system comprising:

• a first lens group having a negative refractive power;
• a second lens group having a positive refractive power;
• and
• an aperture disposed between the first lens group and the second lens group,
• wherein the first lens group and the second lens group are sequentially arranged from an object side to an image side,
• wherein the zoom lens system is configured to perform zooming by moving the second lens group along an optical axis and perform focusing by moving the first lens group along the optical axis,
• wherein the second lens group comprises:
• a fourth lens, a fifth lens, and a sixth lens each having a positive refractive power;
• a seventh lens having a negative refractive power;
• and
• an eighth lens and a ninth lens each having a positive refractive power,
• wherein the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are sequentially arranged from the object side to the image side,
• wherein the zoom lens system satisfies a conditional expression below:
• 3.5<|(vd28−vd27)|/vd26<5.0,
• where vd26, vd27, and vd28 respectively denote Abbe numbers of the sixth lens, the seventh lens, and the eighth lens.