Imaging optical system, and imaging device and camera system provided with imaging optical system

An imaging optical system comprising:

• in order from an object side toward an image side,
• a first lens group having positive power;
• a second lens group having negative power;
• a third lens group having positive power;
• and
• a succeeding lens group including one or more lens groups,
• wherein the third lens group includes
• a lens L3F1 having positive power and
• a lens L3F2 having positive power in order from the object side toward the image side in the third lens group,
• and includes, on the image side than the lens L3F2
• a lens L3R1 having positive power,
• a lens L3R2 having positive power, and
• a lens L3R3 having negative power in order from the image side toward the object side in the third lens group,
• one optical surface of the lens L3R2 and one optical surface of the lens L3R3 are bonded to each other,
• the lens L3R1 moves so as to have a component to move in a direction perpendicular to an optical axis, and optically corrects image blur, and
• the succeeding lens group includes
• a fourth lens group having negative power and being located closest to the object side in the succeeding lens group,
• and a lens group having positive power,
• during zooming from a wide angle end to a telephoto end in imaging, at least the second lens group and the third lens group move in an optical axis direction such that a distance between the second lens group and the third lens group changes.