| 摘要 |
<p>This specification discloses a zoom lens which has, in succession from the object side, a first lens unit of positive refractive power, a second lens unit of negative refractive power for focal length change, a third lens unit for correcting the changing of an imaging plane resulting from a focal length change, and a fourth lens unit of positive refractive power, and in which an aspherical surface AS1 is provided on at least one lens surface constituting the first lens unit and satisfying 1.65<hw/ht and 1.15<hw/hz, where ht is the maximum incidence height of an on-axis light beam, hw is the incidence height of an off-axis light beam of a maximum angle of view at the wide angle end, and hz is the incidence height of the off-axis light beam of a maximum angle of view at a zoom position at a variable power ratio Z<1/4 >, and the power disposition and achromatism condition of the first lens unit, a focusing system, etc. are appropriately set. <IMAGE></p> |
