Zoom lens and image pickup apparatus and image pickup system having the same

An image pickup apparatus comprising:

• a zoom lens;
• and
• an image sensor configured to receive light of 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 second lens unit having a negative refractive power;
• a third lens unit having a positive refractive power;
• a fourth lens unit having a positive refractive power;
• and
• a fifth lens unit having a negative refractive power,
• wherein during zooming, each distance between adjacent lens units changes,
• wherein during zooming from a wide-angle end to a telephoto end, the first lens unit moves toward the object side, a distance between the third lens unit and the fourth lens unit decreases, and a distance between the fourth lens unit and the fifth lens unit decreases,
• wherein the number of optical elements each having a refractive power in the first lens unit is two or less, and
• wherein the following inequalities are satisfied:
• 0.50<f1/f3<2.70
• 0.18<|M34/M45|<0.70
• 0.530≤f1/ft<0.7
• where f1 represents a focal length of the first lens unit, f3 represents a focal length of the third lens unit, M34 represents a changing amount in the distance between the third lens unit and the fourth lens unit during zooming from the wide-angle end to the telephoto end, M45 represents a changing amount in the distance between the fourth lens unit and the fifth lens unit during zooming from the wide-angle end to the telephoto end, and ft represents a focal length at the telephoto end of the zoom lens.