Patent ID: 7417684
Filing Date: 2008-08-26
Classification: G02B

Abstract:
1. 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 shutter is located on an optical axis in a space at a position different from that of a space where said aperture stop is located, said zoom lens comprises, at least, a lens group having negative refracting power and a lens group located just after an image side thereof and having positive refracting power, a spacing between said lens group having negative refracting power and said lens group having positive refracting power is narrower at a telephoto end than at a wide-angle end, said aperture stop is located between the surface located nearest to an image plane side of said lens group having negative refracting power and the surface located nearest to an image plane side of said lens group having positive refracting power, and said shutter is located nearer to the image plane side rather than to said aperture stop, said shutter is located in an air separation just after said lens group having positive refracting power, and said system constantly satisfies the following condition (26): where α′ is an axial distance from said aperture stop to said shutter located nearer to an image side, and β′ is an axial distance from said shutter to an image pickup plane of said electronic image pickup device.