Optical system and imaging apparatus including optical system

An imaging apparatus comprising:

• an optical system;
• and
• an imaging element configured to receive an image formed by the optical system,
• wherein the optical system includes a front group including one or more lens groups, an aperture stop, and a rear group including one or more lens groups, the front group, the aperture stop, and the rear group being disposed in this order from an object side to an image side, intervals between lens groups adjacent to each other being changed during focusing,
• wherein the rear group includes a focus lens group A including at least one positive lens and at least one negative lens,
• wherein the focus lens group A moves toward the image side when focused from infinity to a close distance,
• wherein the front group includes a first lens group having a positive refractive power and a focus lens group B disposed in this order from the object side to the image side,
• wherein, during focusing from infinity to the close distance, the first lens group is stationary relative to an image plane, and the focus lens group A and the focus lens group B move in an optical axis direction relative to the image plane,
• wherein the focus lens group A moves in a direction including a component in a direction perpendicular to an optical axis to correct an image shake, and
• wherein the following conditional inequality is satisfied:
• 0.48
• ≤
• (
• -
• β
• )
• ≤
• 5.
• ,
• where β denotes an image magnification of the optical system at a closest focus.