Focusing mechanism for varifocal objective
AssigneeJos. Schneider Optische Werke Kreuznach GmbH & Co. KG
InventorWolfgang Schroeder
Life of this patent
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Abstract
A varifocal objective with a four-component front lens group, including axially shiftable second and third components, is provided with a focusing mechanism for the joint displacement of these second and third components as well as a further lens member relatively to the axially fixed first component, that further lens member being either the fourth component of the front lens group or part of an otherwise fixed rear lens group. In the case of an afocal front lens group the last three components thereof are displaced in unison by the focusing mechanism. The lens shifts can be co-ordinated by electric servomotors under the control of stored data.
Claims8
In a vertical objective comprising a plurality of coaxial lens members constituting an axially fixed object-side first component, an axially shiftable second component following said first component, an axially shiftable third component following said second component, a fourth component following said third component and an image-side fifth component following said fourth component, the combination therewith of:
- zooming means operatively coupled with said second and third components for axially shifting same at different rates to selectively vary the overall focal length of the objective while maintaining a stationary image plane beyond said further lens members;
- and
- focusing means operatively coupled with said second and third components for jointly shifting same to vary the distance at which objects can be sharply focused on said image plane, one of said lens members disposed on the image side of said third component being axially shiftable and operatively coupled with said focusing means for displacement thereby concurrently with said second and third components to maintain the selected overall focal length.
Dependencies are inferred from the claim text.