Zoom lens focusing system

Claim 1

A zoom lens system comprising: four lens components including, in order from the object side, a first convergent lens component, a second divergent lens component, a third lens component and a fourth convergent lens component, said second and third lens components being movable for zooming, said second lens component serving mainly as a variator and said third lens component serving mainly to maintain the focusing distance constant, said four lens components including an afocal region downstream of said third lens component, where the downstream direction is defined as the direction away from said object side, all of the lenses from said second lens component to said afocal region comprising a focusing lens component, and wherein focusing adjustment to compensate for object distance variation is carried out by integrally moving said focusing lens component with respect to said first convergent lens component to thereby reduce the degradation of aberration due to object distance variation.