Zoom lens and image pickup apparatus

An apparatus comprising:

• a zoom lens;
• and
• an image pickup element configured to pick up an image formed by the zoom lens,
• wherein the zoom lens includes, in order from an object side to an image side:
• a first lens unit having a positive refractive power;
• a plurality of lens units each of which moves in zooming;
• and
• a final lens unit having a positive refractive power,
• wherein an interval between each pair of adjacent lens units changes in zooming,
• wherein the plurality of lens units includes a lens unit having a negative refractive power,
• wherein the first lens unit includes a negative lens and a positive lens,
• wherein at least a part of the first lens unit moves for focusing,
• wherein the first lens unit includes a negative lens made of a material satisfying the following inequalities:
• 1.70<Ndn<1.85,
• 28<vdn<39, and
• −0.010<θn−(0.641682−0.001623×vdn)<−0.004,
• where Ndn denotes a refractive index with respect to a d-line, vdn denotes an Abbe number based on a d-line, and θn denotes a partial dispersion ratio with respect to a g-line and an F-line, and
• wherein the zoom lens satisfies the following inequality:
• 2.0<vbg/vdn<3.5,
• where vbg denotes a maximum value of an Abbe number based on d-line of at least one positive lens included in the first lens unit.