Patent ID: 7688519

Claim:
A zoom lens comprising, in order from an object side to an image side: a first optical unit having a positive refractive power; a second optical unit having a negative refractive power; a third optical unit including an aperture; a fourth optical unit having a positive refractive power; and a fifth optical unit having a positive refractive power, wherein the second optical unit includes a negative lens member and a prism in that order from the object side to the image side, and is stationary during zooming, wherein, when zooming is performed from a wide-angle end to a telephoto end, the first, third, and fourth optical units are moved so that a distance between the first optical unit and the second optical unit is increased, a distance between the second optical unit and the third optical unit is reduced, and a distance between the third optical unit and the fourth optical unit is reduced, and wherein the following conditions are satisfied: 0.20 <|f 2|/√{square root over (( fW·fT ))}<0.45 0.80 <|fN/fW|< 1.90 2.70 <L/fW< 4.20 where fw and fT represent focal lengths of an entire system at the wide-angle end and the telephoto end, respectively, f2 represents a focal length of the second optical unit, fN represents a focal length of the negative lens member, a length of the prism in a light-axis direction is an air conversion length, and L represents a distance on the light axis from a lens surface of the second optical unit closest to the object side to the aperture at the wide-angle end.