Zoom lens and image pickup apparatus including the same

An image pickup apparatus comprising:

• a zoom lens including, in order from an object side to an image side:
• a first lens unit having positive refractive power that does not move for zooming;
• a second lens unit having negative refractive power that moves during zooming;
• a zoom lens unit including at least one lens unit that moves during zooming;
• a stop;
• and
• a fixed lens unit that does not move for zooming,
• wherein the first lens unit includes, in order from the object side to the image side:
• a first sub lens unit having negative refractive power that does not move for focusing;
• a second sub lens unit having positive refractive power that moves toward the image side during focusing from an object at infinity to an object at a close range;
• and
• a third sub lens unit having positive refractive power that moves toward the object side during focusing from an object at infinity to an object at a close range, and
• wherein the following expressions are satisfied:
• −15.0<f1/f2<−2.0,
• −0.25<Ok/D<0.15, and
• |β13/β12|<0.1,
• where f1 represents a focal length of the first lens unit, f2 represents a focal length of the second lens unit, Ok represents a distance from a vertex of a surface closest to the image side in the first lens unit to an image side principal point position of the first lens unit in a state in which an object at infinity is focused, a direction from the object side to the image side being regarded as positive, D represents a thickness of the first lens unit on an optical axis in the state in which an object at infinity is focused, and β12 and β13 respectively represent lateral magnifications of the second sub lens unit and the third sub lens unit in the state in which an object at infinity is focused;
• and
• a solid-state image pickup element for receiving light of an image formed by the zoom lens.