Patent ID: 8165463

Claim:
An electronic imaging apparatus having a zoom optical system, the electronic imaging apparatus comprising: a zoom optical system in which a most object-side lens unit A includes one biconcave-shaped negative lens component, each of air-contact-surfaces of which is configured as an aspherical surface, and when a magnification of the zoom optical system is changed in a range from a wide-angle position to a telephoto position, the lens unit A is moved back and forth along an optical axis in such a way that the lens unit A is initially moved toward an image side; and an electronic imaging unit that has an electronic image sensor in the proximity of an imaging position of the zoom optical system so that an image formed through the zoom optical system is picked up by the electronic image sensor and image data picked up by the electronic image sensor are electrically processed and can be output as image data whose format is changed, wherein in nearly infinite object point focusing, the zoom optical system satisfies the following condition: 0.7 <y 07 /( fw ·tan ω 07w )<0.94 where y 07 is expressed by y 07 =0.7y 10 when y 10 denotes a distance from a center to a point farthest from the center (a maximum image height) within an effective imaging surface (an imageable surface) of the electronic image sensor, ω 07w is an angle made by a direction of an object point corresponding to an image point that is formed distant from the center of the imaging surface by y 07 on the imaging surface at the wide-angle position with the optical axis, and fw is a focal length of an entire system of the zoom optical system at the wide-angle position, and wherein the zoom optical system has a lens unit B adjacent to the lens unit A, and the lens unit B includes a single lens component and a cemented lens component, or three lenses.