Optical system and imaging apparatus including the same

An optical system of which a focal length of an entire system is shorter than a back focus, wherein, when an image stabilizing lens unit, which moves in a direction including a component perpendicular to an optical axis to move an imaging position, is arranged at a position adjacent to an aperture diaphragm on an image side, a cemented lens obtained by cementing a positive lens and a negative lens is arranged on an object side of the aperture diaphragm, the focal length of the entire system is set to f, a focal length of the image stabilizing lens unit is set to fis, a focal length of the cemented lens is set to fc, a distance on the optical axis from the aperture diaphragm to a lens surface on the object side of the image stabilizing lens unit is set to Dis, and a distance on the optical axis from a first lens surface on a side closest to an object to a final lens surface on a side closest to an image when an infinite-distance object is brought into focus is set to DL, condition equations

• 0.00<Dis/DL<0.25,
• 0.3<fis/f<3.5, and
• 0.3<−fc/fis<3.5
• are satisfied.