Zoom lens assembly for photographic cameras
AssigneeElmo Co., Ltd.
InventorMasahiko Nonogaki
Life of this patent
Estimating the term…
Abstract
A zoom lens assembly for photographic cameras, particularly for movie cameras, has a focussing ring, a zooming ring and a fixed-tube for supporting these rings as well as associated lenses. A locking device is provided for locking the focussing ring at the hyperfocal position and at the same time for restricting the zooming range to one in which a sharp image can be produced independently from the zooming operation with the focussing lens being set at the hyperfocal position.
Claims4
In a zoom lens assembly for a photographic camera including a focussing ring, a zooming ring and a stationary fixed tube for supporting said rings and associated lens, the improvement comprising means for making operation of the lens assembly free from the necessity of focussing for certain conditions of the lens assembly, said improvement comprising locking means for fixing said focussing ring at a hyperfocal position on said fixed tube and means cooperating with said locking means for restricting the rotation and hence the zooming range of said zooming ring, whereby a sharp image will be recorded at said hyperfocal position of said focussing ring as set by said locking means, through the restricted zooming range, said focussing ring having an engaging means thereon, said zooming ring being rotatable around the optical axis and being blocked against axial movement and having an engagement means thereon for cooperating with an engaging means for defining the rotation of said zooming ring in said restricted zooming range, and said lens assembly further comprising an intermediate ring between said focussing ring and said zooming ring, said intermediate ring being fixed to said fixed tube and having an engagement means thereon for engagement with said engaging means on said focussing ring for blocking movement of said focussing ring, and having an engaging means thereon for engagement with said engagement means on said zooming ring when said engaging means on said focussing ring is engaged with said engagement means of said intermediate ring.
In a zoom lens assembly for a photographic camera including a focussing ring, a zooming ring and a stationary fixed tube for supporting said rings and associated lens, the improvement comprising means for making operation of the lens assembly free from the necessity of focussing for certain conditions of the lens assembly, said improvement comprising locking means for fixing said focussing ring at a hyperfocal position on said fixed tube and means cooperating with said locking means for restricting the rotation and hence the zooming range of said zooming ring, whereby a sharp image will be recorded at said hyperfocal position of said focussing ring as set by said locking means, through the restricted zooming range, said focussing ring having a projection thereon, and said zooming ring being rotatable around the optical axis while being blocked against axial movement and having a circumferential recess therein defining said restricted zooming range, and said lens assembly further comprising an intermediate ring between said focussing ring and said zooming ring, said intermediate ring being fixed to said fixed tube and having a notch therein, and an axially movable means which is engagable with said recess in said zooming ring when said projection on said focussing ring is engaged with said notch in said intermediate ring for defining a constant position of focus.
Dependencies are inferred from the claim text.