Zoom lens

Claim 2

A lens comprising a housing member and having first, second, third and fourth lens groups from an object end to an image end, respectively, in said housing, said first lens being axially movable of said housing for fine focusing, said fourth lens being stationary in said housing, a lens tube included in said housing, said second and third groups being movable axially within said tube, first guide means for moving said second and third groups simultaneously in a first predetermined non-linear relationship of relative movement to vary the effective focal length of said lens, and second guide means for moving said second and third groups simultaneously and equally in a second predetermined relationship of relative movement for close focusing of said lens.

Claim 3

The lens of claim 1 wherein said first guide means are first and second slots in said tube having directional components along the length of the tube, said second and third groups are each carried in first and second mounts within said tube, pins extending from said mounts into said first and second slots so that said mounts move in said tube in accordance with the contours of said first and second slots, third and fourth slots in said tube having substantially the same contours with directional components along the length of the tube, a first transfer slot joining said first and third slots at one end thereof, a second transfer slot joining said second and fourth slots at one end thereof so that said pins may be transferred to move in either said first and second slots or in said third and fourth slots.

Claim 4

The lens of claim 2 wherein the pin on said second mount extends through a longitudinal slot in said first mount, a selector ring disposed about said tube having a recess therein adapted to receive said pin from said second mount when said second and third groups are positioned for the longest effective focal length of said lens, said selector ring being rotatable with respect to said tube to engage said pin from said second mount and move said pins through said first and second transfer slots to move in either said first and second slots or in said third and fourth slots.

Claim 5

The lens of claim 3 further including a roOm ring movable longitudinally with respect to said tube and coupled to the pin of said first mount for producing movement of said second and third groups.

Claim 6

The lens of claim 4 wherein means are provided to couple said zoom ring to said first group so that said first group may be moved for focusing upon rotation of said tube.

Claim 7

The lens of claim 1 further including selector means for choosing either said first or second guide means for a mode of operation of said lens.

Claim 8

The lens of claim 6 further including means for locking said selector means when said lens is in a selected mode of operation.

Claim 9

The lens of claim 7 wherein said selector means is a selector ring disposed at least partially about said tube and rotatable thereon between two predetermined positions to select the mode of operation.

Claim 10

The lens of claim 8 further including a mount for said second group, means on said mount for releasing said locking means when said mount is positioned for the maximum effective focal length of said lens.

Claim 11

A lens comprising a tube member, first and second lens groups within said tube member, first guide means on said tube for moving said lens groups axially in a first predetermined non-linear relationship to vary the effective focal length of said lens, second guide means for moving said lens groups axially and equally in a second predetermined relative relationship to close focus said lens, transfer means interconnecting said guide means for shifting control of movement of said lens groups between said first and second guide means, and means coupled to said lens groups and movable axially of said tube for moving said lens groups in accordance with either of said guide means.

Claim 12

A lens comprising a tube member, first and second lens groups within said tube member, first guide means on said tube for moving said lens groups axially in a first predetermined non-linear relationship to vary the effective focal length of said lens, second guide means for moving said lens groups axially and equally in a second predetermined relative relationship to close focus said lens, transfer means interconnecting said guide means for shifting control of movement of said lens groups between said first and second guide means, and means coupled to said lens groups and movable axially of said tube for moving said lens groups in accordance with either of said guide means.

Claim 13

The lens of claim 10 wherein said first guide means is a first pair of guide slots having axial directional components, said second guide means is a second pair of guide slots having axial directional components, said transfer means are first and second transfer slots connecting ends of said first and second guide slots, said lens groups being carried in mounts therefor within said tube, first and second followers extending from said first and second mounts, respectively, into one of a pair of said slots, one of said mounts being disposed within the other of said mounts with the follower thereof extending through an axial slot in the other of said mounts, a member slidable on said tube and engaging the follower of said outer mount, a selector member rotatable with respect to said tube and having a peripheral recess receiving the extending end of the follower of the inner mount when said lens groups are in a position to provide the longest effective focal length, said selector member upon rotation thereof being operative to move said followers in said transfer slots between said pairs of guide slots.

Claim 14

The lens of claim 11 further including locking means for normally preventing rotation of said selector member, and means on said outer mount for releasing said locking means when said lens groups are positioned for the longest effective focal length.

Claim 15

The lens of claim 12 wherein said selector member has a recess defined therein from an edge thereof, biasing means urging said locking member into said recess, said means on said outer mount being effective to engage said locking member and move it against said biasing means from said recess.

Claim 16

The lens of claim 13 wherein said selector member has two recesses therein, and said locking member is adapted to move into either recess to lock said selector for a selected mode of operation of said lens.

Claim 17

In a lens system, first and second relatively movable lenses, a tube, first and second lens mounts for said first and second lenses in said tube, a first pair of cam slots defined in said tube, a follower on each of said mounts adapted to extend into one of said first pair of cam slots so that said mounts may be moved in accordance with the contour of said first pair of cam slots to vary the focal length of saId lens system, a second pair of cam slots in said tube, a pair of transfer slots interconnecting a cam slot of each pair to permit said followers to be transferred between said first and second pairs of slots, said second pair of cam slots being contoured to predetermine a different relative movement of said mounts from said first slots for close focusing of said lens system, selector means for positioning said mounts for movement under control of either pair of cam slots, and means coupled to said mounts for moving said mounts in a selected pair of slots.

Claim 18

In a lens system, first and second relatively movable lenses, a tube, first and second lens mounts for said first and second lenses in said tube, a first pair of cam slots defined in said tube, a follower on each of said mounts adapted to extend into one of said first pair of cam slots so that said mounts may be moved in accordance with the contour of said first pair of cam slots to vary the focal length of saId lens system, a second pair of cam slots in said tube, a pair of transfer slots interconnecting a cam slot of each pair to permit said followers to be transferred between said first and second pairs of slots, said second pair of cam slots being contoured to predetermine a different relative movement of said mounts from said first slots for close focusing of said lens system, selector means for positioning said mounts for movement under control of either pair of cam slots, and means coupled to said mounts for moving said mounts in a selected pair of slots.

Claim 19

The lens system of claim 15 wherein one of said mounts is disposed within the other of said mounts, an axial slot in the other of said mounts, the follower of said one of said mounts extending through said axial slot to one of a selected pair of said cam slots.