Abstract: A camera zoom lens system comprising; means for generating and storing a first information signal representing a predetermined position of the first movable lens group, means for generating a second information signal whose value determines a relationship between the respective positions of said first and second movable lens groups, first computing means for deriving from the stored first information signal a third signal representing the position to which the second movable lens group must move so that both lens groups produce an in-focus image of the object at infinity, second computing means responsive to the first and second information signals for generating a correction signal which when combined with the third signal produces an output signal representing the position to which the second movable lens group must move so that both lens groups will produce an in-focus image of an object at a specified distance, third computing means responsive to the correction signal and the third signal for generating a

Abstract: An apparatus for recording information in the form of a two dimensional array of miniature images on a recording material such as electrophotographic, photographic or photochromic material. Means are included for forming those images (by such of the processes of sensitizing, charging, exposing, developing or fixing as are appropriate to the particular material used) from originals or copies of legible size. A facility is provided to form one or more miniature images occupying only part of a storage member on one occasion, and to record a further such image or images on later occasions. Guide means and propulsion means in two dimensions are included for adjusting the relative positions of the storage member and the image forming or image viewing device so that any image space may be presented to the image forming device and any image may be presented to an image viewing device.

Abstract: A thermoplastics data storage member carries information which can be imaged using non-coherent light and, in addition to and distinct from that information, control data which defines a two-coordinate system for the member which controls random access to the information. A reading apparatus comprises a non-laser optical system for imaging selected areas of the information and a servo-system, including a microprocessor and transducers for reading the control data, for positioning a reading head of the optical system in desired locations relative to the storage member. The invention affords cheap optical data bases readable by apparatus not requiring a laser optical system.

Abstract: A hand held digital read-out measuring instrument in which interference fringes are generated by the transmission of radiations through gratings which move relative to one another according to a distance being measured and the fringes are counted to detect changes in the fringe pattern and generate a pulse output related to the distance, means being provided to control the rate of movement and to exert a substantially constant force on the movable elements.