Optical system and imaging apparatus having the same

An optical system comprising a plurality of lens units,

• wherein the plurality of lens units consist of, 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 positive refractive power;
• and
• a third lens unit having a negative refractive power,
• wherein a distance between adjacent lens units changes during focusing,
• wherein the second lens unit moves during the focusing,
• wherein the third lens unit consists of, in order from an object side to an image side, a first partial unit, a second partial unit, and a third partial unit,
• wherein the second partial unit moves in a direction including a component orthogonal to an optical axis during image stabilization, and
• wherein the following conditional expression is satisfied:
• −0.20<f3/f<−0.05;
• and
• −4.00<(1−β3B)×β3C<−2.00,
• where f is a focal length of the optical system focused on an object at infinity and f3 is a focal length of the third lens unit, β3B is a lateral magnification of the second partial unit, and β3C is a lateral magnification of the third partial unit.