Patent ID: 7420611

Claim:
An electronic image pickup system comprising: a zoom lens and an electronic image pickup device located on an image plane side of said zoom lens, wherein said zoom lens comprises a plurality of lens groups in which a spacing between adjacent lens groups is varied to change a focal length and an aperture stop located in an optical path to limit a diameter of an axial light beam, wherein: said aperture stop is of fixed stop shape, and a filter for making light quantity adjustments by a change of transmittance is located on an optical axis in a space at a position different from that of a space where said aperture stop is located, and when a full-aperture F-number, F, of said zoom lens at a telephoto end thereof is 1.5×10 3 a 1 mm <F with respect to the minimum pixel pitch a (in mm) of said electronic image pickup device, a length of said aperture stop in a direction vertical or horizontal to an image pickup plane is longer than a length of said aperture stop in a diagonal direction with respect to the image pickup plane or when a full-aperture F-number, F, of said zoom lens at a telephoto end thereof is 1.5×10 3 ×a/1 mm>F with respect to the minimum pixel pitch a (in mm) of said electronic image pickup device, a length of said aperture stop in a direction vertical or horizontal to an image pickup plane is shorter than a length of said aperture stop in a diagonal direction with respect to the image pickup plane.