Patent ID: 7315425
Filing Date: 2008-01-01
Classification: G02B

Abstract:
1. A zoom lens comprising: plurality of lens units wherein magnification change is performed by moving only one lens unit among the plurality of lens units, focus adjustment of the zoom lens is performed by moving one of a first lens unit and a second lens unit counted from an enlargement conjugate side among the plurality of lens units, and the zoom lens is approximately telecentric on reduction conjugate side of the zoom lens, wherein the plurality of lens units include a first lens unit having negative refractive power, a second lens unit having positive refractive power, a third lens unit having positive refractive power, and a fourth lens unit having positive refractive power in this order from an enlargement conjugate side, wherein the magnification changing is performed by moving only the third lens unit in an optical axis direction of the zoom lens, wherein focus adjustment is performed by moving the second lens unit on an optical axis, wherein when a focal distance of the third lens unit is referred to as “f