Zoom lens and image pickup apparatus including the same

An image pickup apparatus, comprising:

• a zoom lens comprising, in order from an object side to an image side:
• a first lens unit having a positive refractive power that does not move for zooming;
• a second lens unit having a negative refractive power that moves during zooming;
• and
• an N-th lens unit having a positive refractive power that does not move for zooming, the N-th lens unit being arranged closest to the image side,
• wherein the first lens unit comprises, in order from the object side to the image side:
• a first sub-lens unit having a negative refractive power that does not move for focusing;
• a second sub-lens unit having a positive refractive power that moves along an optical axis during focusing;
• and
• a third sub-lens unit having a positive refractive power that does not move for focusing, and
• wherein the following conditional expressions are satisfied:
• 1.5<f1/fw<3.5;
• and
• −2.70<βnw<−1.45,
• where f1 represents a focal length of the first lens unit, fw represents a focal length at a wide angle end of the zoom lens, and βnw represents a lateral magnification at a wide angle end of the N-th lens unit when an axial ray enters from infinity in a state of focusing on the infinity;
• and
• a solid-state image pickup element configured to receive an image formed by the zoom lens.