Zoom lens and image pickup apparatus having the same

An image pickup apparatus comprising:

• a zoom lens;
• and
• a photoelectric conversion element configured to receive light of an image formed by the zoom lens,
• wherein the zoom lens is capable of changing a distance between adjacent lens units in zooming, and
• wherein the zoom lens comprises, in order from an object side to an image side,
• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• an aperture stop;
• a third lens unit having a positive refractive power;
• and
• a rear lens group including at least one lens unit,
• wherein the first lens unit is positioned closer to the object side at a telephoto end than at a wide-angle end,
• wherein the third lens unit includes positive lenses, materials of the positive lenses included in the third lens unit satisfy the following expression:
• θgF3P−(−1.665×10−7·νd3P3+5.213×10−5·νd3P2−5.656×10−3·νd3P+0.737)>0
• 50.0<νd3P<100.0, and
• wherein the following conditional expressions are satisfied:
• 8.0<fT/f3<20.0
• 15.0<f1/fW<30.0
• where θgF3P is a partial dispersion ratio of material of at least one of the positive lenses in the third lens unit, νd3P is Abbe's number of at least one of the positive lenses, fW and fT are focal lengths of a total system at the wide-angle end and at the telephoto end respectively, f1 is a focal length of the first lens unit, and f3 is a focal length of the third lens unit.

A zoom lens capable of changing a distance between adjacent lens units in zooming, the zoom lens comprising:

• in order from an object side to an image side,
• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• an aperture stop;
• a third lens unit having a positive refractive power;
• and
• a rear lens group including at least one lens unit,
• wherein the first lens unit and the aperture stop are positioned closer to the object side at a telephoto end than at a wide-angle end,
• wherein the third lens unit includes positive lenses, materials of the positive lenses included in the third lens unit satisfy the following expression:
• θgF3P−(−1.665×10−7·νd3P3+5.213×10−5·νd3P2−5.656×10−3·νd3P+0.737)>0
• 50.0<νd3P<100.0, and
• wherein the following conditional expression is satisfied:
• 8.0<fT/f3<20.0
• where θgF3P is a partial dispersion ratio of material of at least one of the positive lenses in the third lens unit, νd3P is Abbe's number of at least one of the positive lenses, fT is a focal length of a total system at the telephoto end, and f3 is a focal length of the third lens unit.

An image pickup apparatus comprising:

• a zoom lens;
• and
• a photoelectric conversion element configured to receive light of an image formed by the zoom lens,
• wherein the zoom lens is capable of changing a distance between adjacent lens units in zooming, and
• wherein the zoom lens comprises, in order from an object side to an image side,
• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• an aperture stop;
• a third lens unit having a positive refractive power;
• and
• a rear lens group including at least one lens unit,
• wherein the first lens unit and the aperture stop are positioned closer to the object side at a telephoto end than at a wide-angle end,
• wherein the third lens unit includes positive lenses, materials of the positive lenses included in the third lens unit satisfy the following expression:
• θgF3P−(−1.665×10−7·νd3P3+5.213×10−5·νd3P2−5.656×10−3·νd3P+0.737)>0
• 50.0<νd3P<100.0, and
• wherein the following conditional expression is satisfied:
• 8.0<fT/f3<20.0
• where θgF3P is a partial dispersion ratio of material of at least one of the positive lenses in the third lens unit, νd3P is Abbe's number of at least one of the positive lenses, fT is a focal length of a total system at the telephoto end, and f3 is a focal length of the third lens unit.