Abstract A zoom lens comprises a focusing lens which does not move during zooming, a variator lens which moves along an optical axis in connection with a zooming operation for magnification variation, a compensator which moves in the direction of the optical axis in connection with movement of the variator lens, a first diaphragm member to determine the F-number of the zoom lens, a relay lens, and a second diaphragm member which moves along the optical axis and is positioned behind the above-mentioned variator lens. This second diaphragm member moves in the same direction along the optical axis as, and with a predetermined relationship with the movement of the variator lens. When the variator lens is moved from the compensator lens side toward the focusing lens side (from the telescopic side to the wide side), the second diaphragm member will effect vigneting of the light flux reaching the central part of picture frame so that the vignetting - image height characteristics become almost equal. However, no vignetting is effected on the light flux reaching the peripheral part at the wide end plane where the light volume is basically small. Thus aberration is eliminated at the central part of the picture frame, and no change in the light volume at the periphery of the picture, by the zooming operation, will be effected.
A zoom lens comprising, in combination, a focusing lens; a variator lens moving, during a zooming operation, in the direction of the optical axis of said zoom lens; a compensator lens moving, during a zooming operation, in the direction of said optical axis; a relay lens; a first diaphragm device positioned between said compensator lens and said relay lens to determine the F-number; and a second diaphragm device positioned between said variator lens and said first diaphragm device, said second diaphragm device being movable along said optical axis in the same direction as movement of said variator lens and with a predetermined relationship with the movement of said variator lens.
Claim 2
Dependent Claim
110 words
A zoom lens comprising, in combination, a focusing lens; a variator lens moving, during a zooming operation, in the direction of the optical axis of said zoom lens; a compensator lens moving, during a zooming operation, in the direction of said optical axis; a relay lens; a first diaphragm device positioned between said compensator lens and said relay lens to determine the F-number; and a second diaphragm device positioned between said variator lens and said first diaphragm device, said second diaphragm device being movable along said optical axis in the same direction as movement of said variator lens and with a predetermined relationship with the movement of said variator lens.
Claim 3
Dependent Claim
24 words
A zoom lens as claimed in claim 1, in which said second diaphragm device is positioned between said variator lens and said compensator lens.
Claim 4
Dependent Claim
30 words
A zoom lens, as claimed in claim 1, in which said second diaphragm device is a diaphragm having an aperture adjustable in accordance with movement thereof along said optical axis.