Abstract: A photographic lens including a focus ring rotatable between prescribed end limits corresponding respectively with an infinite focus setting and a relatively close focus setting is provided with an adjustable range stop assembly for selectively setting one end limit at a position corresponding with a focus setting at which scenes or events are anticipated by the photographer. In one preferred form, the range stop assembly comprises a selector switch carried by the focus ring for movement of a control pin between stops on the lens housing wherein one of the stops is defined by a plurality of lands at different circumferential positions whereby the permissible range of focus ring rotation is selected in accordance with the position of the control pin.

Abstract: A photographic lens including a focus ring rotatable about a lens housing between prescribed end limits to displace a focusing lens element between positions corresponding respectively with relatively long and relatively short focus settings, wherein a range stop assembly is provided for selectively adjusting the end limits at focus settings corresponding with positions at which scenes or events are anticipated by the photographer. In a preferred form, the range stop assembly comprises a pair of axially slidable adjustment sleeves normally biased into locked positions for rotation with the focus ring and respectively supporting control pins extending into cam grooves on a fixed portion of the lens housing to define the end limits of focus ring rotation.

Abstract: A locking system is provided for selectively locking the operating ring of a zoom lens against axial displacement with respect to a zoom lens housing to secure optical elements of the zoom lens in a selected position of magnification adjustment. The locking system comprises a cam sleeve concentrically within the operating ring and constrained for axial movement with the operating ring upon adjustment of image magnification. The cam sleeve includes a generally helical cam groove for receiving a cam pin on the lens housing such that the cam sleeve is forced to rotate with respect to the operating ring when the operating ring is moved axially. A slide switch on the operating ring selectively moves a ratchet into locking engagement with a toothed rack at one end of the cam sleeve to prevent relative rotation of the cam sleeve with respect to the operating ring and thereby lock the operating ring against axial movement.

Abstract: A locking system is provided for selectively locking the operating ring of a zoom lens against axial displacement to secure optical elements of the zoom lens in a selected position of magnification adjustment. The locking system comprises a ratchet carried by the operating ring and urged by a spring into locking engagement with a toothed rack mounted on the zoom lens housing to lock the operating ring in a selected axial position of adjustment. A control pin is movable upon depression of a spring-biased button to engage the ratchet and move it away from engagement with the toothed rack to permit axial displacement of the operating ring to an alternative magnification setting. In one embodiment of the invention, a lock-release switch selectively maintains the ratchet away from engagement with the rack.