Abstract A zoom lens system having two movable lens groups disposed between a front focusing lens used only for focusing and a relay lens, wherein normal zoom photography and extremely short distance photography are carried out by shifting said two movable lens groups in the direction of the optical axis, said zoom lens system comprising a cam cylinder having cam grooves formed thereon for shifting said two movable lens groups along the optical axis, a zoom ring for operating said two movable lens groups through said cam cylinder, said cam cylinder and said zoom ring being integrally connected and coaxial with each other, and locking means for preventing said two movable lens groups from entering the extremely short distance photography zone during the normal zoom photography against the intention of the operator taking a photograph.
A zoom lens system comprising a front and rear movable lens group disposed between a front focusing lens used only for focusing and a relay lens, said zoom lens system comprising a cam cylinder having two cam grooves formed thereon for shifting the rear movable lens group along the optical axis while holding the front movable lens group stationary at the limit position for wide angle photographing, a fixed main cylinder provided around said cam cylinder coaxially therewith and having formed therein a cutout for controlling the range of rotation of a zoom ring said zoom ring being provided around said main cylinder coaxially therewith and slidable relative thereto, said zoom ring and said cam cylinder being integrally connected by a pin provided through said cutout of the main cylinder, said zoom ring being formed with a recess at a suitable location of the inner wall thereof opposite to the cutout of said main cylinder, and a locking member provided in said recess and having a locking portion selectively rotatable between a position to project into said cutout and a position not to project into said cutout.
Claim 2
Dependent Claim
187 words
A zoom lens system comprising a front and rear movable lens group disposed between a front focusing lens used only for focusing and a relay lens, said zoom lens system comprising a cam cylinder having two cam grooves formed thereon for shifting the rear movable lens group along the optical axis while holding the front movable lens group stationary at the limit position for wide angle photographing, a fixed main cylinder provided around said cam cylinder coaxially therewith and having formed therein a cutout for controlling the range of rotation of a zoom ring said zoom ring being provided around said main cylinder coaxially therewith and slidable relative thereto, said zoom ring and said cam cylinder being integrally connected by a pin provided through said cutout of the main cylinder, said zoom ring being formed with a recess at a suitable location of the inner wall thereof opposite to the cutout of said main cylinder, and a locking member provided in said recess and having a locking portion selectively rotatable between a position to project into said cutout and a position not to project into said cutout.