Patent ID: 7411731

Claim:
A zoom lens including a varifocal lens unit including a plurality of movable lens groups, and a prism disposed on an image side of the varifocal lens unit, wherein: the prism has an incident plane into which a light flux from the varifocal lens unit enters, and an exit plane from which the light flux is emitted toward an image plane, the exit plane capable of being inclined with respect to an optical axis, the exit plane inclined in accordance with a following conditional expression (1), α= −f×θ/[Bf ( n− 1)] (1) where α: an angle formed by a normal of the exit plane and the optical axis, f: a focus distance of a whole lens system, θ: a turning angle of a lens system, Bf: a distance from the exit plane of the prism to the image plane along the optical axis, and n: a refraction index of the prism.