Optical system and image pickup apparatus including the same

An image pickup apparatus, comprising:

• an optical system;
• and
• an image pickup element configured to receive an image formed by the optical system,
• the optical system comprising, 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;
• and
• a third lens unit having a positive refractive power,
• wherein, during focusing from infinity to a close distance, the second lens unit moves toward the image side, and an interval between each pair of adjacent lens units is changed,
• wherein the first lens unit consists of, in order from the object side to the image side:
• a first lens sub-unit having a negative refractive power, which does not move for image stabilization;
• a second lens sub-unit having a positive refractive power, which moves during the image stabilization;
• and
• a third lens sub-unit, which does not move for the image stabilization,
• wherein the second lens sub-unit includes a meniscus positive lens LIS having a concave surface facing the object side, and
• wherein the following conditional expression is satisfied:
• 0.78<DB/DL<0.95,
• where DL represents a distance from a lens surface closest to the object side in the first lens unit to an image plane when focusing at infinity, and DB represents a distance from a lens surface closest to the object side in the second lens sub-unit to the image plane when focusing at infinity.