Lens apparatus and imaging system including the same

A lens apparatus comprising:

• an imaging optical system including a plurality of lenses;
• a movable member holding at least one lens among the plurality of lenses and configured to move in a direction including a component perpendicular to an optical axis of the imaging optical system;
• a fixed member whose movement in the direction is restricted;
• a coil provided at one of the movable member or the fixed member and configured to move the movable member in the direction;
• a magnet provided at the other of the movable member or the fixed member and configured to move the movable member in the direction;
• and
• a first shield member configured to cover at least a part of the coil as viewed in a direction parallel to the optical axis and as viewed in the direction perpendicular to the optical axis, at least a part of the first shield member being arranged closer to an image plane than the coil,
• wherein the imaging optical system includes a lens unit having a positive refractive power and arranged closer to the image plane than the at least one lens, the lens unit being fixed while the movable member moves in the direction, and
• wherein the lens apparatus satisfies the following expression:
• 0.8≤|fis/fp|≤8.0
• where a focal length of the at least one lens is represented by fis, and a focal length of the lens unit is represented by fp.