Rear-focus type zoom lens with movable second and fourth lens units for zooming and focusing

摘要

A rear focus type zoom lens including, in succession from the object side, a first lens unit of positive refractive power, a second lens unit of negative refractive power, a third lens unit of positive refractive power having a stop, the third lens unit having at least two positive lenses and a negative lens which is most adjacent to the image plane side, and a fourth lens unit of positive refractive power consisting of a positive lens and a negative lens, the second lens unit and the fourth lens unit being moved to effect zooming, the fourth lens unit being moved to effect focusing.