A zoom lens comprising lens units, wherein the lens units consist of, in order from an object side to an image side: a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; a focus lens unit having a negative refractive power and configured to move toward the image side during focusing from infinity to a short distance; and a final lens unit having a positive refractive power, disposed closest to the image side, or a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; a third lens unit having a positive refractive power; a focus lens unit having a negative refractive power and configured to move toward the image side during focusing from infinity to a short distance; and a final lens unit having a positive refractive power, disposed closest to the image side, or a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; a focus lens unit having a negative refractive power and configured to move toward the image side during focusing from infinity to a short distance; a fourth lens unit having a negative refractive power; a final lens unit having a positive refractive power, disposed closest to the image side, wherein intervals between adjacent lens units are configured to vary during at least one of zooming and focusing, and wherein conditional expressions 3.5 < f img / f w < 10.0 − 5.0 < f f / f w < − 1.0 , and 2.0 < BF w / f w < 4.5 are satisfied where a focal length of the final lens unit is f img , a focal length of the focus lens unit is f f , a focal length of an entire system at a wide angle end is f w , and a back focus at the wide angle end is BF w . a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; a focus lens unit having a negative refractive power and configured to move toward the image side during focusing from infinity to a short distance; and a final lens unit having a positive refractive power, disposed closest to the image side, or a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; a third lens unit having a positive refractive power; a focus lens unit having a negative refractive power and configured to move toward the image side during focusing from infinity to a short distance; and a final lens unit having a positive refractive power, disposed closest to the image side, or a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; a focus lens unit having a negative refractive power and configured to move toward the image side during focusing from infinity to a short distance; a fourth lens unit having a negative refractive power; a final lens unit having a positive refractive power, disposed closest to the image side, wherein intervals between adjacent lens units are configured to vary during at least one of zooming and focusing, and wherein conditional expressions 3.5 < f img / f w < 10.0 − 5.0 < f f / f w < − 1.0 , and 2.0 < BF w / f w < 4.5 are satisfied where a focal length of the final lens unit is f img , a focal length of the focus lens unit is f f , a focal length of an entire system at a wide angle end is f w , and a back focus at the wide angle end is BF w . <EOS>