Zoom lens system

A zoom lens system comprising a plurality of lens groups, wherein a deflector which deflects an optical axis of said zoom lens system is positioned between lens groups which are movable for zooming, said movable lens groups comprising first and second movable lens groups having optical axes which intersect at substantially a right angle, said zoom lens system consisting of three lens groups,

• wherein said zoom lens system satisfies the following conditions:
• 0<log10Z2/log10Z<0.4
• 0.2<fw/f3<0.6
• −1.3<m3t<−0.8
• wherein
• Z2=m2t/m2w;
• Z=ft/fw;
• m2t designates the transverse magnification of said second lens group at the long focal length extremity;
• m2w designates the transverse magnification of said second lens group at the short focal length extremity;
• ft designates the focal length of the entire lens system at the long focal length extremity;
• fw designates the focal length of the entire lens system at the short focal length extremity;
• f3 designates the focal length of the third lens group;
• and
• m3t designates the transverse magnification of said third lens group at the long focal length extremity.

A zoom lens system comprising a plurality of lens groups, a mirror which deflects an optical axis of said zoom lens system being positioned between first and second lens groups which are movable upon zooming, optical axes of said first and second lens groups intersecting, no lens group being positioned between said first and second lens groups and said mirror, wherein said zoom lens system satisfies the following condition:

• 0.25<DMmin/ft<0.8
• wherein
• DMmin=DMa+DMb;
• DMa designates the minimum distance from the lens group immediately before said mirror to the center of said mirror which is defined as the intersecting point where the optical axis meets the reflection surface of said mirror;
• DMb designates the minimum distance from the center of said mirror to the lens group immediately behind said mirror;
• and
• ft designates the focal length of the entire lens system at the long focal length extremity.

A zoom lens system comprising a plurality of lens groups, a prism which deflects an optical axis of said zoom lens system being positioned between first and second lens groups which are movable upon zooming, optical axes of said first and second lens groups intersecting, no lens group being positioned between said first and second lens groups and said prism, wherein said zoom lens system satisfies the following condition:

• 0.8<DPmin/2y<1.5
• wherein
• DPmin=DPa+(Lp/Np)+DPb;
• DPa designates the minimum distance from the lens group immediately before said prism to said prism;
• Lp designates the axial thickness of said prism along the optical axis;
• Np designates the refractive index of said prism;
• DPb designates the minimum distance from said prism to the lens group immediately behind said prism;
• and
• 2y designates the image size determined by the optical system according to the relationship y=f x tan W where f represents the focal length of the entire lens system, and W represents the half angle-of-view.