Abstract: A zoom lens system includes: a first lens group having positive power; a second lens group having negative power; a third lens group having positive power; a fourth lens group having negative power; and a fifth lens group having positive power. The first lens group is made up of a single lens. The second lens group is made up of four lenses. The zoom lens system is configured to zoom from a wide-angle end toward a telephoto end such that the fifth lens group does not move but the first to fourth lens groups move to change intervals between the lens groups.

Abstract: A zoom lens system includes: a first lens group having positive power; a second lens group having negative power; a third lens group having positive power; a fourth lens group having negative power; and a fifth lens group having positive power. The first lens group is made up of a single lens. The second lens group is made up of four lenses. While the zoom lens system is zooming from a wide-angle end toward a telephoto end during a shooting session, the fifth lens group does not move but the first to fourth lens groups move to change intervals between the lens groups.

Abstract: A method for improving spectral, spatial, and temporal stability of semiconductor lasers and their beam profile uniformity based on statistical average of plural transient or unsteady state longitudinal and lateral modes that are continuously perturbed. A laser module implementing the method comprises a semiconductor laser, a drive circuit generating RF-modulated drive current, and an automatic power control loop for producing stable, low noise and uniform or nearly uniform illumination field along one or two dimensions.