Zoom lens and image pickup apparatus having 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 and configured not to move for zooming;
• a second lens unit having a negative refractive power and configured to move for zooming;
• a third lens unit having a negative refractive power and configured to move for zooming;
• a fourth lens unit having a negative refractive power and configured to move for zooming;
• and
• a relay lens unit having a positive refractive power and configured not to move for zooming, wherein
• the second lens unit is configured to move to the image side from a wide-angle end to a telephoto end,
• a distance between the second lens unit and the third lens unit is narrower at a zoom state between the wide-angle end and the telephoto end than that at the wide-angle end, and
• a conditional expression
• 0.05<L2 min/L2w<0.98
• is satisfied where L2 min is a minimum distance between the second lens unit and the third lens unit in a zoom range from the wide-angle end to a zoom state corresponding to a focal length fx, and L2w is a distance between the second lens unit and the third lens unit at the wide-angle end, wherein the focal length fx is defined by an expression
• fx=fw×Z0.38,
• where fw is a focal length of the zoom lens at the wide-angle end, and Z is a zoom ratio of the zoom lens;
• and
• an image pickup element configured to pick up an image formed by the zoom lens.